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

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

x = ± 6i

step-by-step explanation:

x^2 = -36

take the square root of each side

sqrt(x^2) = sqrt(-36)

we know sqrt(ab) = sqrt(a) sqrt(b)

x = ±sqrt(36) sqrt(-1)

we know that sqrt (-1) = i

x = ± 6i