Question

31. What is the solution to the system of equations? -7x-2y+z=-2 6x-y-z=-18 5x+4y-z=18

Answer 1

Answer:

x = -1, y = 7, z = 5

1. -7 -2 -1 -2
2. 6 -1 -1 -18
3. 5 4 -1 18

use 2. - 3.

= -1 -5 0 -36 --- 4.

use 1. + 2.

= -1 -3 0 -20 --- 5.

use 4. + 5.

= 0 -8 0 -56

=> y = 7

y = 7 back into 5.:

x - 35 = -36

=> x = -1

x = -1 and y = 7 back into 1.:

7 - 14 + z = -2

=> z = 5