Question

what is the first step when rewriting $y = -4x^2 + 2x - 7$ in the form $y = a(x - h)^2 + k$?
$x$ must be factored from $-4x^2 + 2x$
$-4$ must be factored from $-4x^2 + 2x$
$2$ must be factored from $2x - 7$
$-4$ must be factored from $-4x^2 - 7$

Explanation:

To rewrite a quadratic function $y=ax^2+bx+c$ into vertex form $y=a(x-h)^2+k$, the first step is to factor the coefficient of $x^2$ from the terms containing $x$ (the $x^2$ and $x$ terms). For $y=-4x^2+2x-7$, the coefficient of $x^2$ is $-4$, so we factor $-4$ from $-4x^2+2x$.

Answer:

-4 must be factored from $-4x^2 + 2x$