$-2x-x^2-2$ $=-(x^2+2x+2)$ $=-(x^2+2x.1+1+1)$ $=-(x+1)^2-1$ Ta thấy: $-(x+1)^2≤0$ $→-(x+1)^2-1<0$ Reply
$-2x-x^2-2$
$=-(x^2+2x+2)$
$=-(x^2+2x.1+1+1)$
$=-(x+1)^2-1$
Ta thấy: $-(x+1)^2≤0$
$→-(x+1)^2-1<0$