Answer:
<B=45°
Step-by-step explanation:
<A=<B (alternate angles)
5x-15=2x+21
5x-2x=21+15
3x=36
Dividing both sides by 3
x=12
Now
<A=5(12)-15
=60-15
=45°
<B=2(12)+21
=24+21
