Question

For what value of x is line a parallel to line b? Enter your answer in the box. x =

Answer 1

The angles with measures 5x + 15 and 115 are corresponding angles.
For lines a and b to be parallel, those angles must be congruent.

5x + 15 = 115

5x = 100

x = 20

Answer 2

5x+15=115
subtract 15 from both sides
5x=100
divide both sides by 5
x=20