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

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

Step-by-step explanation:

-7x - 2y + z = -2  (1)

6x -  y - z  =  -18(2)

5x + 4y - z=  18(3)

Subtract equations (2) - (3):

x  - 5y = -36(4)

Add equations (1) and (2):

-x  - 3y = -20(5)

Adding (4) and (5):

-8y = -56

y = 7.

Substitute y = 7 into equation 4:

x - 5(7) = -36

x - 35 = -36

x = -1.

Substitute x = -1 and y = 7 in equation (1):

-7(-1) - 2(7) + z = -2

7 - 14 + z = -2

z = -2 - 7 + 14

z =  5.