abc math pls help

Complementary angles sum to 90°

So we have

(3x - 10) + (2x + 10)  = 90    simplify

5x  = 90    divide by 5 on each side

x = 18

The answer is a.

Explanation:

Complementary angles are two angles that add up to 90 degrees.

So (3x-10) + (2x+10) would have to equal 90                 (3x-10) + (2x+10) = 90

We simplify it. The 10s cancel each other out                   3x - 10 + 2x +10 = 90

                                                                                   5x = 90

We simplify again                                                           x = 18