Answer:

a = 40°

Step-by-step explanation:

Formula:

a + b = 90 because if two angles is called complimentary angles if their measures add to 90°.

Given: a = 3x - 5; b = 2x + 20

Substitute the given.

( 3x - 5 ) + ( 2x + 20 ) = 90

Combined like terms.

3x + 2x -5 + 20 = 90

Then, simplified.

5x + 15 = 90

move the constant 15 to the right

5x = 90 - 15

5x = 75

Divide both sides by 5

5x / 5 = 75 / 5

x = 15

Find the measure of a.

If the measure of angle a is 3x - 5 then, 3(15) - 5 = 45 - 5 = 40°.

I'm not sure about the measure of b. So, I just did 2x + 20. . In case I used a wrong given just take this as your examples. Thank youu.