# How do you find the maximum value of # y = -x^2 + 8x - 4#?

##### 1 Answer

Oct 20, 2016

12

#### Explanation:

and

As such we have maximum (as

When

Note: As this is a quadratic and the coefficient of

Incidentally, this can also be fond without calculus by completing the square:

So maximum of

graph{-x^2 + 8x -4 [-16.17, 23.83, -4.8, 15.2]}