Question

Two angles are supplementary if their measures add up to 180°. If one of two supplementary angles is (3x + 7)° while the other is (5x - 11), then x =

A.25
B.21
C.24
D.20
E.23

Answer 1

E. 23

Step-by-step

3x + 7 + 5x - 11 = 180

* add 3x and 5x

8x + 7 - 11 = 180

* do 7-11

8x - 4 = 180

* add 4 to both sides to cancel it out

8x = 184

* divide 8 on both sides to get x alone

x = 23