Question

How do you write `y = (x+1)(x-3)` into vertex form?

Answer 1

The vertex form is:

`y-y_v=a(x-x_v)^2`.

So:

`y=(x+1)(x-3)rArry=x^2-3x+x-3rArr`

`y=x^2-2x-3rArry=x^2-2x+1-1-3rArr`

`y=(x-1)^2-4rArry+4=(x-1)^2`.