# What is the vertex of # y= -8x^2+8x-(x+9)^2#?

##### 1 Answer

May 19, 2017

A sort of cheat method (not really)

#### Explanation:

Expanding the brackets we get:

As the coefficient of

Thus the vertex is a maximum.

Consider the standardised form of

Part of the process of completing the square is such that:

Substitute for

Note that