Question

I need help please it’s for math

Answer 1

139

Explanation:

Since the given is a parallelogram then angle <D and angle <B are equal angles

10x - 21 = 9x - 5

10x - 9x = 21 - 5

x = 16 replace x with 16 to find the measure of angle <B

16*9 - 5 = 139