Answer:
x = 12
m(∠B) = 45°
Step-by-step explanation:
Given question is incomplete; find the complete question in the attachment.
In the figure attached two lines 'l' and 'm' are the parallel lines and line 'n' is a transverse.
Angles A and B are the "Alternate exterior angles" which will equal in measure.
m(∠A) = m(∠B)
(5x - 15) = (2x + 21)
5x - 2x = 15 + 21
3x = 36
x = 12
Since, m(∠B) = (2x + 21)
= (2×12) + 21
= 24 + 21
= 45°
Therefore, x = 12 and measure of angle B will be 45°.
