Answer:
x = 9
Step-by-step explanation:
Adjacent angles A and D are supplementary:
(30 +5x)° +(15 +10x)° = 180°
15x +45 = 180 . . . . . collect terms, divide by °
15x = 135 . . . . . . . . . subtract 45
135/15 = x = 9 . . . . . divide by the coefficient of x
The value of x is 9.
