Question

What is the vertex form of `y= x^2-21x`?

Answer 1

`(x - 21/2)^2 - 441/4`

Explanation:

`x^2 -21x`
`= x^2 - 21x + (-21/2)^2 - (-21/2)^2`
`= (x - 21/2)^2 - 441/4`