Suppose ∠A and ∠B are complementary angles, m∠A = (3x + 5) °, and m∠B = (2x - 15) °. Solve for x and then find m∠A and m∠B

Two angles are complementary when they add up to 90° ⇒

∠A + ∠B = 90°

3x + 5 + 2x - 15 = 90

5x - 10 = 90

5x = 90 + 10

5x = 100

x = 100/5

x = 20

m∠A = 3x + 5 = 3*20 + 5 = 60 + 5 = 65 °

m∠B = 2x - 15 = 2*20 - 15 = 40 - 15 = 25 °