Question

-5x +3y +6z=4
-3x + y + 5z=-5
-4x + 2y + z= 13

Answer 1

x=-2, y=4, z=-3

Explanation:

(1) -5x +3y +6z=4

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

(3) -4x + 2y + z= 13

(1)-(2)-(3)

-5x +3y +6z - (-3x + y + 5z) - (-4x + 2y + z) = 4-(-5)-13

-5x+3x+4x = 9-13

2x=-4

x=-2

put back in (2)

-3(-2) + y + 5z=-5

y + 5z = -11

multiply by 2

2y + 10z = -22

subtract from (3)

10z - (-4(-2) + z) = -22-13

9z - 8 = -35

9z=-27

z=-3

substitute x n z back in, y=4

Answer 2

See the attached image for solution: