1.

The sum of 3 numbers is 20 .If we multiple the 3rd number by 2 and first number to the result we get 23.By adding 2nd and 3rd numbers to 3 times the first number we get 46 .Find the numbers by using cramer's rule.​

Answer»

X+Y+Z=20

2X+Y-Z=23

3X+Y+Z=46 ADD THE SECOND & THIRD EQUATIONS.

------------------

5X+2Y=69

ADD THE FIRST & SECOND EQUATIONS.

X+Y+Z=20

2X+Y-Z=23

-----------------

3X+2Y=43 NOW ADD THIS EQUATION TO THE PREVIOUS SUM TIMES -1.

-5X-2Y=-69

------------------

-2X=-26

X=-26/-2

X=13 ANS.

5*13+2Y=69

65+2Y=69

2Y=69-65

2Y=4

Y=4/2

Y=2 ANS.

13+2+Z=20

15+Z=20

Z=20-15

Z=5 ANS.

PROOF:

2*13+2-5=23

26-3=23

23=23


Discussion

No Comment Found

Related InterviewSolutions