Optimal Value

The highest or lowest value that the graph reaches

To find the optimal value or the y value in the vertex, just substitue the x value (axis of symmetry) into the original factored form equation.

Example

Therefore

The optimal value is y=-9 and the vertex is (5,-9)

Question

What is the optimal value of y=(x-4)(x-20) ?

Solution

Therefore

The optimal value is y=-64

y=(x-2)(x-8)

x=2+8

2

x=5

y=(x-2)(x-8)

y=(5-2)(5-8)

y=(3)(-3)

y=-9

y=(x-4)(x-20)

x=4+20

2

x=12

y=(x-4)(x-20)

y=(12-4)(12-20)

y=(8)(-8)

y=-64