Question

Solve the system and type expressions for x and y in terms of z.

2x-y-7z=1, and -3x+y-z=-4

Answer 1

2x-y-7z  = 1----------> (1)

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

To eliminate the y value add the equations (1) and (2).

2x-y-7z = 1

-3x+y-z = -4

__________

-x-8z = -3

-x = 8z-3

x = -8z+3

Substitute the x value in (2).

-3(-8z+3)+y-z = -4

24z-9+y-z = -4

23z+y = -4+9

23z+y = 5

y = 5-23z

y = -23z+5

To check substitute the x,y in equation (3)

-3(-8z+3)-23z+5-z = -4

-24z-9-23z+5-z = -4

-4 = -4

Solutions of given system interms of z

x = -8z+3 and y = -23z+5

Comments

Your answer is correct .

But typo mistake in check.

24z - 9 - 23z + 5 - z = - 4

- 4 = - 4