Za and Zb are complementary angles. Za measures 59º. What is the measure of Zb?

Complementary angles are two angles whose sum adds up to 90 degrees
Za + Zb = 90
You know Za measures 59
59 + Zb = 90

Solution: Zb is 31 degrees

Zb = 31

Step-by-step explanation:

Complementary angles mean that the angles add up to 90 so:

Za + Zb = 90

59 + Zb = 90

Zb = 90 - 59

Zb = 31

The vertex form of a quadratic function:
(h,k) - the coordinates of the vertex 

If a>0, then the parabola opens upwards, so the vertex is the minimum of the function.
If a<0, then the parabola opens downwards, so the vertex is the maximum of the function.

a=-1<0
the vertex is maximum

a=1>0
the vertex is minimum