Question

calcule. x2 +8z+16=0

Answer 1

 Presumo que a equação seja $x^2+8x+16=0$, se sim,

$x^2+8x+16=0\\\\x^2+2\cdot\,x\cdot4+4^2=0\\\\(x+4)^2=0\\\\(x+4)(x+4)=0\\\\x+4=0\\\\\boxed{x=-4}$