Question

How do I use the vertex formula to determine the vertex of the graph for `y=2x^2-4x`?

Answer 1

The vertex form for a quadratic equation is
`y=m(x-a)^2+b`
where the vertex is located at `(a,b)`

`y=2x^2-4x`

`y=2(x^2-2x) " extract the "m" coefficient"`

`y=2(x^2-2x+1)-2 " complete the square"`

`y=2(x-1)^2-2`

and the vertex is at `(1,-2)`