Question

For the following system, if you isolated x in the second equation to use the substitution method, what expression would you substitute into the first equation?

3x + y = 8
−x − 2y = −10

A.) −2y + 10
B.) 2y + 10
C.) 2y − 10
D.) −2y − 10

Answer 1

A.) −2y + 10

Explanation:

−x − 2y = −10

Add 2y to both sides.

-x = 2y - 10

Multiply both sides by -1.

x = -2y + 10