Question

x^-7x-8>=0

^ квадрат
>= больше или равно

Answer 1

D = $b^{2}$ -4ac =49+32=81=$9^{2}$
$x_{1} = \frac{-b- \sqrt{D} }{2a} = \frac{7-9}{2}$ =-1
$x_{2} = \frac{-b+ \sqrt{D} }{2a} = \frac{7+9}{2} =8$
x∈ [-1 ;8]