Question

How can you solve this system of equations using substitution?
-66x-2z=-196
8x+2z=22

Answer 1

In the second equation:

Subtract 8x from both sides.

2z = 22 - 8x

Divide 2 on both sides.

z = 11 - 4x

Plug this into the first equation.

-66 - 2(11 - 4x) = -196

-66 - 22 + 8x = -196

Combine like terms.

-88 + 8x = -196

Add 88 to both sides.

8x = -108

Divide 8 on both sides.

x = -13.5

Put this into the second equation.

8(-13.5) + 2z = 22

-108 + 2z = 22

Add 108 to both sides.

2z = 130

Divide 2 on both sides.

z = 65

and

x = -13.5

Hope this helps!