Question

quanto  e (x+2)  ao  quadrado -(x+4)  ao  quadrado +4x+12?

Answer 1

$(x+2)^2-(x+4)^2=4x+12\\x^2+4x+4-(x^2+8x+16)=4x+12\\x^2+4x+4-x^2-8x-16=4x+12\\-4x-12=4x+12\\\\\boxed{-8x-24=0}$

Extra : Se quiser o valor de x , basta isolar:

$-8x-24=0\\x=\frac{-24}{8}=-3$