Answer:

Explanation:
Complementary angles are two angles that add up to 90°.
We know the measurements of m∠ZA and m∠ZB, so their angle measures will add to 90°.

Let's simplify this equation so we have x on one side of the equation.

Now that we know the value of
, we can substitute it inside the equation for m∠ZB (
)

Hope this helped!