Question

Помогите срочно !!!!!!!!!!!!-x^2-2x+8>0 ????????????

Answer 1

$-x^2-2x+8\ \textgreater \ 0 \\ \\ x^2+2x-8\ \textless \ 0 \\ \\ \Delta=4+32=36=6^2 \\ \\ x_1= \frac{-2-6}{2}=-4;x_2= \frac{-2+6}{2}=2 \\ \\ \iff (x-2)(x+4)\ \textless \ 0 \iff x\in (-4;2)$