| 1. |
Find the equation of the straight lines each passing through the point ( 6 , -2 )and whose sum of the intercepts is 5 |
|
Answer» Answer: GIVEN :– ▪︎ Straight line passing from point (6,-2). ▪︎ Sum of intercepts = 5 TO FIND :– Equation of straight line . SOLUTION :– ▪︎ Intercept FORM of line is – \begin{lgathered}\\ \implies \: { \boxed{ \bold{ \dfrac{x}{a} + \dfrac{y}{b} = 1 }}} \\\end{lgathered} ⟹ a x
+ b y
=1
\begin{lgathered}\\ \to \: { \bold{Here \: a \: \: and \: \: b \: \: are \: \: x - intercept \: \: and \: \: y - intercept \: \: respectively.}} \\\end{lgathered} →Hereaandbarex−interceptandy−interceptrespectively.
▪︎ According to the question line passing from a point (6,-2) , So that – \begin{lgathered}\\ \implies{ \bold{ \dfrac{6}{a} + \dfrac{( - 2)}{b} = 1 \: \: \: \: - - - - eq.(1)}} \\\end{lgathered} ⟹ a 6
+ b (−2)
=1−−−−eq.(1)
• And sum of intercepts = 5 \begin{lgathered}\\ \implies{ \bold{ a + b= 5 \: \: \: \: - - - - eq.(2)}} \\\end{lgathered} ⟹a+b=5−−−−eq.(2)
▪︎ Now by eq.(1) and eq.(2) – \begin{lgathered}\\ \implies{ \bold{ \dfrac{6}{a} + \dfrac{( - 2)}{(5 - a)} = 1 }} \\\end{lgathered} ⟹ a 6
+ (5−a) (−2)
=1
\begin{lgathered}\\ \implies{ \bold{ \dfrac{6(5 - a) - 2(a)}{a(5 - a)} = 1 }} \\\end{lgathered} ⟹ a(5−a) 6(5−a)−2(a)
=1
\begin{lgathered}\\ \implies{ \bold{ \dfrac{30- 6a- 2a}{a(5 - a)} = 1 }} \\\end{lgathered} ⟹ a(5−a) 30−6a−2a
=1
\begin{lgathered}\\ \implies{ \bold{ \dfrac{30 - 8a}{a(5 - a)} = 1 }} \\\end{lgathered} ⟹ a(5−a) 30−8a
=1
\begin{lgathered}\\ \implies{ \bold{ 30 - 8a = 5a - {a}^{2} }} \\\end{lgathered} ⟹30−8a=5a−a 2
\begin{lgathered}\\ \implies{ \bold{ {a }^{2} - 13A + 30 = 0 }} \\\end{lgathered} ⟹a 2 −13a+30=0
\begin{lgathered}\\ \implies{ \bold{ {a }^{2} - 10a - 3a + 30 = 0 }} \\\end{lgathered} ⟹a 2 −10a−3a+30=0
\begin{lgathered}\\ \implies{ \bold{ a(a - 10) - 3(a - 10 )= 0 }} \\\end{lgathered} ⟹a(a−10)−3(a−10)=0
\begin{lgathered}\\ \implies{ \bold{( a - 3)(a - 10) = 0 }} \\\end{lgathered} ⟹(a−3)(a−10)=0
\begin{lgathered}\\ \implies{ \bold{a = 3 \: , \: a = 10 }} \\\end{lgathered} ⟹a=3,a=10
• Now using eq.(2) – \begin{lgathered}\\ \implies{ \bold{b = 2 \: , \: b = - 5 }} \\\end{lgathered} ⟹b=2,b=−5
EQUATION :– (1) When a = 3 , b = 2 :– \begin{lgathered}\\ \implies \: { \boxed{ \bold{ \dfrac{x}{3} + \dfrac{y}{2} = 1 }}} \\\end{lgathered} ⟹ 3 x
+ 2 y
=1
(2) When a = 10 , b = -5 :– \begin{lgathered}\\ \implies \: { \boxed{ \bold{ \dfrac{x}{10} + \dfrac{y}{ (- 5)} = 1 }}} \\\end{lgathered} ⟹ 10 x
+ (−5) y
=1
|
|