equations in 7th grade math

Question

One of two supplementary angles is 112 degrees. Let x = the measure of the other supplementary angle. Write and solve an equation to find the measure of angle x.

Answer 1

Two supplementary angles add up to 180° like this:

m∠A + m∠B = 180°

In your case one angle is 112° and the other angle is x° so the equation is:

112 + x = 180 [now subtract 112 from both sides of the equation to get:

x = 68°