Complementary= 90 degrees
So, m<A and m<B are equal to 90 degrees.
2x+18+2x+24= 90
2x+2x=4x
18+24= 42
4x+42= 90
Subtract 42 on both sides.
4x= 48
Divide by 4 into both sides.
x=12
Now, plug in x for m<A.
2(12)+18
24+18
42
m<A equals
42.
We can check this by seeing if m<B's final result makes 42+m<B= 90
2(12)+24
24+24
48
48+42= 90
I hope this helps!
~kaikers