Answer:
x = 12, B = 45°
Explanation:
In the attachment,
A = C (vertically opposite angles)
C = B (corresponding angles)
•°• A = B
_________
A = B
5x - 15 = 2x + 21
5x - 2x = 21 + 15
3x = 36
x = 36/3
x = 12
B = 2x + 21°
B = 2(12) + 21
B = 24 + 21
B = 45°
=》See the attachment.
Hope it helps ⚜