Explore topic-wise InterviewSolutions in .

This section includes InterviewSolutions, each offering curated multiple-choice questions to sharpen your knowledge and support exam preparation. Choose a topic below to get started.

31401.

आवृत्ति वितरण में विषमता है ऐसा कब कहा जाता है ?

Answer»

संमितता या सुडोलता की कमीवाले आवृत्ति वितरण में विषमता है ऐसा कहेंगे ।

31402.

एक आवृत्ति वितरण के तीन चतुर्थक 42, 36 और 40 है, तो आवृत्ति वितरण का प्रकार बताइए ।

Answer»

यहा Q1 = 36, Q3 = 42, M = 40 होगा । Q3 – M > M – Q1 है इसलिए ऋण विषमतावाला आवृत्ति वितरण है ।

31403.

संमित आवृत्ति वितरण किसे कहते है ?

Answer»

यदि समष्टि के अवलोकन भूयिष्ठक के मूल्य से दोनों ओर समान रीति से वितरित हुए हो एसे आवृत्ति वितरण को संमित आवृत्ति वितरण कहते है।

31404.

जब खुल्ला शिरावाला आवृत्ति वितरण और एक से अधिक भूयिष्ठक हो तब विषमतांक कौन से सूत्र से प्राप्त करोगे?

Answer»

एक से अधिक भूयिष्ठकवाला आवृत्ति वितरण हो तब भूयिष्ठक के स्थान पर माध्यिका ज्ञात करके निम्न सूत्र का उपयोग करेंगे ।
\(j = \frac{3(\bar X−M)}S\)

31405.

एक धन विषम आवृत्ति वितरण का विषमतांक 0.75 है । यदि प्र. विचलन 20 और माध्य 37.50 हो, तो M ज्ञात करो।

Answer»

यहाँ j = 0.75, S = 20, \(\overline X\) = 37.50 है ।

∴ j = \(\frac{3(\overline X−M)}S\)

0.75 = \(\frac{3(37.50−M)}{20} \frac{0.75×20}3\) = 37.50 – M

5 = 37.50 – M

∴ M = 37.50 – 5

∴ M = 32.50

31406.

यदि किसी आवृत्ति वितरण में (Q3 – Q2) < (Q2 – Q1) हो, तो आवृत्ति वितरण का प्रकार बताइए ।

Answer»

यदि किसी आवृत्ति वितरण में (Q3 – Q2) < (Q2 – Q1) हो, तो ऋण आवृत्ति वितरण होगा ।

31407.

एक आवृत्ति वितरण में Q3 – Q2 = 2 (Q2 – Q1) हो, तो j ज्ञात करो ।

Answer»

j = \(\frac{(Q_3−Q_2)−(Q_2−Q_1)}{(Q_3−Q_2)+(Q_2−Q_1)}\)

Q3 – Q2 के स्थान पर 2 (Q2 – Q1) रखने पर

∴ j = \(\frac{2(Q_2−Q_1)−1(Q_2−Q_1)}{2(Q_2−Q_1)+1(Q_2−Q_1) }\)\(\frac{1}2\)

j = 0.33

31408.

Which of the following statements is true for a symmetric distribution?(a) Q3 = 2M – Q1(b) Q2 – Q3 = Q2 – Q1(c) Q3 + Q1 &gt; 2M(d) Q3 + Q1 &lt; 2M

Answer»

Correct option is (a) Q3 = 2M – Q1

31409.

एक आवृत्ति वितरण की विषमता SK = – 2.8 है । यदि उसका भूयिष्ठक 48.8 हो, तो माध्य ज्ञात करो ।

Answer»

SK =\( \overline X\) – MO MO = 48.8 दिया है ।

∴ – 2.8 = \( \overline X\) – 48.8

∴ – 2.8 + 48.8 = \( \overline X\)

\( \overline X\)= 46 माध्य = 46

31410.

संमित आवृत्ति वितरण के लिए कौन-सा विधान सत्य है ? (A) Q3 = 2M – Q1(B) Q2 – Q3 = Q2 – Q1(C) Q3 + Q1 &gt; 2M(D) Q3 + Q1 &lt; 2M

Answer»

सही विकल्प है (A) Q3 = 2M – Q1

31411.

एक आवृत्ति वितरण के लिए Q3 + Q1 = 125 और M = 62.5 है, तो आवृत्ति वितरण की विषमता के बारे में क्या कह सकते हो ?

Answer»

यहाँ Q3 + Q1 – 2M = 0 होता है । 125 – 2 × 62.5 = 125 – 125 = 0 इसलिए संमित आवृत्ति वितरण है ।

31412.

एक आवृत्ति वितरण में Q3 + Q1 = 1.5 M और 3(Q3 – Q1) = 2M हो, तो j ज्ञात करो ।

Answer»

यहाँ Q3 + Q1 = 1.5 M रखने पर

और Q3 – Q1  =\(\frac{2M}3 \)रखने पर

∴ j = \(\frac{Q_3+Q_1−2M}{Q_3−Q_1}=\frac{1.5−2M}{0.67M}=\frac{−0.5M}{0.67M}\)

∴ j = – 0.75

31413.

विषम आवृत्ति वितरण की परिभाषा दीजिए और उसके लक्षण बताइए ।

Answer»

सममितियता का अभाव अर्थात् विषमता । उसके लक्षण निम्नलिखित है :

  1. जिस आवृत्ति वितरण का आवृत्तिवक्र संपूर्ण घंटाकार का न हो ऐसा आवृत्ति वितरण विषम है ।
  2. जिस आवृत्ति वितरण का माध्य, मध्यका और भूयिष्ठक समान नहीं अर्थात् \(\overline X\) # M # MO वह विषम आवृत्ति वितरण है ।
  3. जिस आवृत्ति वितरण में चतुर्थक मध्यका से समान अन्तर पर न आये हो उस आवृत्ति वितरण विषम है ऐसा कहेंगे । .
  4. यदि मध्य में आये वर्ग का महत्तम आवृत्ति से दोनों ओर समान अन्तर पर आये वर्गों की आवृत्तियाँ समान न हो वह
    विषम आवृत्ति वितरण है ।
  5. जिस आवृत्तिवक्र का आवृत्तिवक्र के दोनों किनार अधिक खिचा हुआ होता है ।
31414.

Which of the following statements is false?(a) If Q3 + Q1 &gt; 2M the distribution is positively skewed.(b) Bowley’s coefficient of skewness is found using positional averages.(c) The absolute measure is divided by standard deviation in Karl Pearson’s method to eliminate the effect of unit of the variable whereas in Bowley’s method, the absolute measure is divided by the difference of quartiles.(d) The frequencies of observations which are equidistant on both sides of the mode are equally distributed in a skewed distribution.

Answer»

Correct option is (d) The frequencies of observations which are equidistant on both sides of the mode are equally distributed in a skewed distribution.

31415.

आवृत्ति वितरण में यदि Q3 + Q1 = 60 और M = 30 हो, तो उसकी विषमता के लिए कौन-सा विधान सत्य है :(A) आवृत्ति वितरण अधिक विषम है।(B) आवृत्ति वितरण कम विषम है।(C) आवृत्ति वितरण में संमितता की कमी है।(D) आवृत्ति वितरण संमित है ।

Answer»

सही विकल्प है (D) आवृत्ति वितरण संमित है ।

31416.

Write the formula of quartile deviation.

Answer»

Coefficient of quartile deviation

= (Q3 - Q1)/(Q + Q1)

Here, Q3 = upper quartile, Q1 = Lower quartile.

31417.

Algebraic sum of deviations from mean is :(A) Negative(B) Positive(C) Different in each(D) Zero

Answer»

Answer is (C) Different in each

31418.

Coefficient of Range can be defined as –(A) (H - L)/2(B) (H + L)/2(C) (H - L)/(H + L)(D) (H + L)/(H - L)

Answer»

Answer is (C) (H - L)/(H + L)

31419.

Temperature of 7 days in a city are given in centigrade 18, 12, 6, -7, -12, 5, -4. Then range in centrigrade will be –(A) 6(B) 30(C) 22(D) 14

Answer»

Answer is (B) 30

Range = Max. Value – Min. Value

= 18 – (- 12) 

= 18 + 12 = 30

31420.

Find the coefficient of range of the following data –Size10-1515-2020-2525-30Frequency2468

Answer»

Lower limit (S) = 10

Upper limit (L) = 30

Range = (L - S)/(L + S)

= (30 - 10)/(30 + 10)

= 20/40

= 1/2 = 0.5

Thus Range coefficient is 0.5.

31421.

Find the formula to find standard deviation in individual series.

Answer»

σ = √((∑x2)/n - ((∑x)/n)2)

31422.

If maximum cost of any times is Rs 500 and minimum Rs 75, then coefficient of range will be –(A) 0.739(B) 0.937(C) 7.39(D) 73.9

Answer»

Answer is (A) 0.739

Range coefficient

= (500 - 75)/(500 + 75) = 425/575

= 0.739

31423.

If value of all the terms of a series are same, then find value of dispersion.

Answer»

Value of dispersion is zero because dispersion (deviation) cannot be find for same values.

31424.

If variance (σ) = √(∑fd2/k - (∑fd/30)2) then value of k is –(A) 10(B) 20(C) 30(D) 60

Answer»

Answer is (C) 30

Formula (σ) = √(∑fd2/k - (∑fd/30)2)

k = 30

31425.

Coefficient of range of variable series 10, 20, 30, 40, 50, 60 is –(A) 3/2(B) 5/6(C) 7/5(D) 5/7

Answer»

Answer is (D) 5/7

Coefficient of Range

= (60 - 10)/(60 + 10) = 50/70 = 5/7

31426.

Marks obtain by five students in math are 20, 25, 15, 35 and 30 its range will be :(A) 15(B) 20(C) 25(D) 30

Answer»

Answer is (B) 20

Range = Maximum value – minimum value 

= 35 – 15 = 20

31427.

Evaluate out range and coefficient of range of the marks.Marks5−910−1415−1920−2425−2930−34No. Students463264

Answer»

To get the range and its coefficient, first we have to convert inclusive class intervals into exclusive class intervals.

Class IntervalExclusive Class IntervalFrequency
5 − 94.5 − 9.54
10 −149.5 − 14.56
20 −2419.5 − 24.52
25 −2924.5 − 29.56
30− 3429.5 − 34.54

Range = Upper limit of the highest class interval − Lower limit of the lowest class intervalor, Range = 34.5 − 4.5 = 30 

Coefficient or Range = \(\frac{H-L}{H+L}=\frac{34.5-4.5}{34.5+4.5}=\frac{30}{39}\) = 0.769

Hence, the range is 730 marks and coefficient of range is 0.769.

31428.

From the following data calculate range and coefficient of range:Marks15253545556575No. of Students9118352074

Answer»
MarksNo. of Students
159
2511
358
4535
5520
657
754

Highest value (H) = 75

Lowest value (L) = 15

Range = Highest value − Lowest value

or, R = 75 − 15= 60 marks

Coefficient of Range = \(\frac{H-L}{H+L}=\frac{75-15}{75+15}=\frac{60}{90}=0.66\)

Hence, range is 60 and coefficient of range is 0.66

31429.

The weight (in kg) for 10 students are 53, 47, 60, 55, 71, 65, 61, 68, 63, 70. What is the range of the data?(a) 17 kg(b) 23 kg(c) 24kg(d) 18kg

Answer»

Correct option is (c) 24kg

31430.

The height of 11 men were 61, 64, 68, 69, 67, 68, 66, 70, 65, 67 and 72 inches. Calculate the range If the shortest man is omitted, what is the percentage change in the range?

Answer»

1. Range = L = S = 72 – 61 = 11 inches.

2. New Range (Shortest man is omitted)

= L – S = 72 – 64 = 8

change in range =11 – 8 = 3 inches

Percentage change in range = 3/11 x 100 = 27.2%

31431.

Find the sum of the series 101 + 99 + 97 + .... + 47.

Answer»

In this case, we have to first find the number of terms. 

Here a = 101, l = Tn = 47, d = 99 – 101 = –2 

∴ 47 = 101 + (n – 1) × (–2), where n = number of terms 

⇒ 47 = 101 – 2n +2 

⇒ 2n = 103 – 47 = 56 ⇒ n = 28 

∴ Sn = \(\frac{n}{2}\) (a + l) 

⇒ S28 = \(\frac{28}{2}\) (101 + 47)  

= 14 × 148 

= 2072.

31432.

In the given figure, the side QR of ΔPQR is produced to a point S. If the bisectors of ∠PQR and ∠PRS meet at point T, then prove that ∠QTR = 1/2 ∠QPR.

Answer»

In ΔQTR, TRS is an exterior angle.

QTR + TQR = TRS

QTR = TRS − TQR (1)

For ΔPQR, PRS is an external angle.

QPR + PQR = PRS

QPR + 2TQR = 2TRS (As QT and RT are angle bisectors)

QPR = 2(TRS − TQR)

QPR = 2QTR [By using equation (1)]

QTR = 1/2 QPR

31433.

In an examination, 70% of the candidates passed in English, 80% passed in Mathematics and 10% failed in both these subjects. If 144 candidates passed in both, then the total number of candidates was (a) 125 (b) 200 (c) 240 (d) 375

Answer»

(c) 240

Let the total number of candidates be x. 

Given, 70% of x passed in English 

80% of x passed in Maths 

144 passed in English and Maths both 

10% of x failed in English and Maths both

\(\therefore\) 90% of x passed in English and Maths both.

\(\therefore\) 90% of x = 70% x + 80% of x – 144

\(\Rightarrow\) 60% of 144

\(\Rightarrow\) x = \(\frac{144\times100}{60}\) = 240.

31434.

In a potato race 20 potatoes are placed in a line at intervals of 4 metres with the first potato 24 metres from the starting point. A contestant is required to bring the potatoes back to the starting place one at a time. How far would he run in bringing back all the potatoes?

Answer»

Given at start he has to run 24m to get the first potato then 28 m as the next potato is 4m away from first and so on

Hence the sequence of his running will be 24, 28, 32 …

There are 20 terms in sequence as there are 20 potatoes

Hence only to get potatoes from starting point he has to run

24 + 28 + 32 + … up to 20 terms

This is only from starting point to potato but he has to get the potato back to starting point hence the total distance will be twice that is

Total distance ran = 2 × (24 + 28 + 32…) … 1

Let us find the sum using he formula to find sum of n terms of AP

That is S= n/2 (2a + (n – 1) d)

There are 20 terms hence n = 20

⇒ S20 = (20/2) (2 (24) + (20 – 1) 4)

On simplification we get

⇒ S20 = 10(48 + 19(4))

⇒ S20 = 10(48 + 76)

On computing we get

⇒ S20 = 10 × 124

⇒ S20 = 1240 m

Using equation 1

⇒ Total distance ran = 2 × 1240

⇒ Total distance ran = 2480 m

Hence total distance he has to run is 2480 m

31435.

Solve:3 (x + 5) = 18

Answer»

3 (x + 5) = 18

=> 3x + 15 = 18

=> 3x = 18 -15 = 3

x = 3/3 = 1

31436.

Solve:7x -3x +2 = 22

Answer»

7x -3x +2 = 22

=> 7x - 3x = 22 - 2

=> 4x = 20

=> x = 20/4

=> x = 5

31437.

A number decreased by 8 equals 26, find the number.

Answer»

Let required number = A

∴ According to the sum :

x – 8 = 26

⇒ A = 26 + 8

⇒ A = 34

∴ Required number = 34

31438.

The sum of three consecutive numbers is 54. Taking the middle number as x, find:(i) expression for the smallest number and the largest number.(ii) the three numbers.

Answer»

Sum of three consecutive numbers = 54

Middle number = x

(i) The first number = x – 1

and third number = x + 1

(ii) ∴ x + x-1+x+1 = 54

⇒ 3x = 54

⇒ x= 54/3 = 18

∴ First number =18-1 = 17

and third number =18 + 1 = 19

∴ Three required numbers are 17, 18,19

31439.

Find three consecutive integers such that their sum is 78.

Answer»

Sum of three consecutive numbers = 78

Let first number = x

Then second number = x + 1

and third number = x + 2

Then x + x+1+x + 2 = 78

⇒ 3x + 3 = 78

⇒ 3x = 78 – 3 = 75

⇒ x = 75/ 3 = 25

∴ First number = 25

Second number = 25 + 1 = 26

and third number = 26 + 1 = 27

Then the three required numbers are 25, 26,27

31440.

13 and 31 is a strange pair of numbers such that their squares 169 and 961 are also mirror images of each other. Can you find two other such pairs?

Answer»

First pair is 12 and 21

Squares of numbers, 122 = 144 and 212 = 441

Second pair is 102 and 201

Squares of numbers, 1022 = 10404 and 2012 = 40401

31441.

Floor of a room is of dimensions 5m × 4m and it is covered with circular tiles of diameters 50 cm each as shown in figure. Find area of floor that remains uncovered with tiles. (use π = 3.14)

Answer»

Length of the floor = l = 5 m

Breadth of the floor = b = 4 m

∴ Area of the floor = l × b = 5 × 4 = 20 m2

Now, Diameter of each circular tile = 50 cm

∴ Radius of each circular tile = r = 25 cm = 0.25 m

Area of one circular tile = πr2

= 3.14 × (0.25)2

= 0.19625 m2

Area of such 80 tiles = 80 × 0.19625

= 15.7 m2

Area of the floor that remains uncovered with tiles = Area of the floor – Area of all 80 circular tiles

= 20 – 15.7 = 4.3 m2

Hence, the required area of floor that remains uncovered with tiles is 4.3 m2.

31442.

A class room is 7m long, 6.5m wide and 4m high. It has one door 3m × 1.4m and three windows each measuring 2m × 1m The interior walls are to be color-washed. The contractor charges Rs. 15per sq. m. Find the cost of colour washing.

Answer»

l = 7m, n = 6.5m and h = 4m 

∴ Area of the room = 2( l + b)h = 2(7 + 6.5) 4 = 108m

Area of door = 3 × 1.4 = 4.2m2 

Area of one window = 3 × 2 = 6m2 

∴ Area of 3 windows = 3 × 2 = 6m2 

∴ Area of the walls of the room to be colour washed = 108 - (4.2 + 6) 

= 108 - 10.2 = 97.8m2 

∴ Cost of colour washing @ Rs. 15 per square metre = Rs. 97.8 × 15 = Rs. 1467.

31443.

Can a normal convex lens behave like a concave lens and vice-versa?

Answer»

Yes. If a lens is kept in a medium whose refractive index is more than that of the material of the lens, the normal convex lens starts behaving like a concave lens and vice-versa.

31444.

The internal and external diameters of a hollow hemispherical vessel are 21 cm and 25.2 cm respectively. The cost of painting 1 cm2 of the surface is 10 paise. Find the total cost to paint the vessel all over.

Answer»

Given that, 

internal diameter of hollow hemisphere, r = 10.5 cm 

External radius, R = 12.6 cm 

Total surface area = 2πR2 + 2πr2 + π(R2 - r2

= 2π(12.6)2 + 2π(10.5)2 + π((12.6)2 – (10.5)2

= 1843.38 cm2 

Given that, 

cost of painting 1 cm2 of surface = 10 paise 

Therefore, total cost to paint 1843.38 cm2\(\frac{1843.38\times10}{100}\)

Rs 184.34

31445.

The water for a factory is stored in a hemispherical tank whose internal diameter is 14 m. The tank contains 50 kL of water. Water is pumped into the tank to fill to its capacity. Calculate the volume of water pumped into the tank.

Answer»

Given: Internal diameter of hemispherical tank = 14 m

Internal radius of hemispherical tank = 14/2 - 7 m

Tank contains 50kl = 50m3 of water (since, 1kl = 1m3)

Volume of a hemispherical tank = 2/3 πr3

Where π = 22/7

r = radius of hemispherical tank

Thus,

Volume of  hemispherical tank = 2/3 x 22/7 x (7)3

= 2156/3

= 718.66 m3

Volume of water pumped into the tank = Volume of hemispherical

tank – 50m3

Volume of water pumped into the tank = 718.66 – 50 = 668.66 m3

31446.

Using factor theorem, factorize the polynomials:x4 – 7x3 + 9x2 + 7x - 10

Answer»

Let f(x) = x4 – 7x3 + 9x2 + 7x- 10 

Constant term = -10 

Factors of -10 are ±1, ±2, ±5, ±10 

Let x – 1 = 0 or x = 1 

f(1) = (1)4 – 7(1)3 + 9(1)2 + 7(1) – 10 

= 1 – 7 + 9 + 7 - 10 

= 0 

f(1) = 0 

Let x + 1 = 0 or x = -1 

f(-1) = (-1)4 – 7(-1)3 + 9(-1)2 + 7(-1) – 10 

= 1 + 7 + 9 – 7 - 10

= 0 

f(-1) = 0

Let x – 2 = 0 or x = 2 

f(2) = (2)4 – 7(2)3 + 9(2)2 + 7(2) – 10 

= 16 – 56 + 36 + 14 – 10

= 0 

f(2) = 0 

Let x – 5 = 0 or x = 5 

f(5) = (5)4 – 7(5)3 + 9(5)2 + 7(5) – 10 

= 625 – 875 + 225 + 35 – 10

= 0 

f(5) = 0 

Therefore, (x – 1), (x + 1), (x – 2) and (x - 5) are factors of f(x)

Hence f(x) = (x – 1) (x – 1) (x – 2) (x - 5).

31447.

Using factor theorem, factorize each of the following polynomial:x3 + 13x2 + 32x + 20

Answer»

Let, f (x) = x3 + 13x2 + 32x + 20

The factors of the constant term + 20 are \(\pm\) 1, \(\pm\) 2,\(\pm\) 4, \(\pm\) 5, \(\pm\) 10 and 20

Putting x = -1, we have

f (-1) = (-1)3 + 13 (-1)2 + 32 (-1) + 20

= -1 + 13 – 32 + 20

= 0

So, 

(x + 1) is a factor of f (x)

Let us now divide

f (x) = x3 + 13x2 + 32x + 20 by (x + 1) to get the other factors of f (x)

Using long division method, we get

x3 + 13x2 + 32x + 20 = (x + 1) (x2 + 12x + 20)

x2 + 2x + 20 = x2 + 10x + 2x + 20

= x (x + 10) + 2 (x + 10)

= (x + 10) (x + 2)

Hence, 

x3 + 13x2 + 32x + 20 = (x + 1) (x + 10) (x + 2)

31448.

Find the greatest common factor (GCF/HCF) of the given polynomials: 9x2, 15x2y3, 6xy2 and 21x2y2

Answer»

We know that the numerical coefficients of given numerical are 9, 15, 16 and 21

Greatest common factor of 9, 15, 16 and 21 is 3.

Common literals appearing in given numerical are x and y

Smallest power of x in four monomials is 1

Smallest power of y in four monomials is 0

Monomials of common literals with smallest power is x

∴ The greatest common factor = 3x

31449.

Using factor theorem, factorize the polynomials:2x4 – 7x3 – 13x2 + 63x – 45

Answer»

Let f(x) = 2x4 – 7x3 – 13x2 + 63x – 45 

Constant term = -45 

Factors of -45 are ±1, ±3, ±5, ±9, ±15, ±45

Here coefficient of x4 is 2. 

So possible rational roots of f(x) are ±1, ±3, ±5, ±9, ±15, ±45, ±1/2,±3/2,±5/2,±9/2,±15/2,±45/2 

Let x – 1 = 0 or x = 1 

f(1) = 2(1)4 – 7(1)3 – 13(1)2 + 63(1) – 45

= 2 – 7 – 13 + 63 – 45 

= 0 

f(1) = 0 

f(x) can be written as, 

f(x) = (x - 1) (2x3 – 5x2 -18x + 45) 

or f(x) = (x - 1) g(x) …(1)

Let x – 3 = 0 or x = 3 

f(3) = 2(3)4 – 7(3)3 – 13(3)2 + 63(3) – 45 

= 162 – 189 – 117 + 189 – 45

= 0 

f(3) = 0 

Now, we are available with 2 factors of f(x), (x – 1) and (x – 3) 

Here g(x) = 2x2 (x-3) + x(x-3) -15(x-3) 

Taking (x-3) as common 

= (x-3)(2x2 + x – 15) 

= (x-3)(2x2+6x – 5x -15)

= (x-3)(2x-5)(x+3)

= (x-3)(x+3)(2x-5) ….(2) 

From (1) and (2) 

f(x) =(x-1) (x-3)(x+3)(2x-5)

31450.

Factorize each of the following polynomials:(i) x3 + 13x2 + 31x - 45 given that x+9 is a factor(ii) 4x3 + 20x2 + 33x + 18 given that 2x+3 is a factor.

Answer»

(i) Let, f (x) = x3 + 13x2 + 31x - 45

Given that (x + 9) is a factor of f (x)

Let us divide f (x) by (x + 9) to get the other factors

By using long division method, we have

f (x) = x3 + 13x2 + 31x - 45

= (x + 9) (x2 + 4x – 5)

Now,

x2 + 4x – 5 = x2 + 5x – x – 5

= x (x + 5) – 1 (x + 5)

= (x – 1) (x + 5)

f (x) = (x + 9) (x + 5) (x – 1)

Therefore, 

x3 + 13x2 + 31x - 45 = (x + 9) (x + 5) (x – 1)

(ii) Let, f (x) = 4x3+20x2+33x+18

Given that (2x + 3) is a factor of f (x)

Let us divide f (x) by (2x + 3) to get the other factors

By long division method, we have

4x3 + 20x2 + 33x + 18 = (2x + 3) (2x2 + 7x + 6)

2x2 + 7x + 6 = 2x2 + 4x + 3x + 6

= 2x (x + 2) + 3 (x + 2)

= (2x + 3) (x + 2

4x3 + 20x2 + 33x + 18 = (2x + 3) (2x + 3) (x + 2)

= (2x + 3)2 (x + 2)

Hence,

4x3 + 20x2 + 33x + 18 = (2x + 3)2 (x + 2)