Quadratic equations

Answer all the questions below and press submit to see how many you got right.

id: 9642

Assume $x^2+2x-4=8$ for some $x$. Calculate $3x^2+6x-12.$

id: 9562

$-3x^2+3x+1=?$ for $x=1$.

id: 9577

$-2x^2+5x+5=?$ for $x=0$.