Maverick and Mack were each asked to factor the quadratic expression $-k^2+4k+21$. Their responses are shown below. **Maverick** ||| **Mack** :-:|:-:|:-:|:-: $-1(k-3)(k+7)$ ||| $(-k+3)(k+7)$ **Which student wrote an expression that is equivalent to $-k^2+4k+21$ ?** [[☃ radio 1]]