X в квадрате +9 x+8>=0

Х²+9х+8≥0; D=9²-4*8=81-32=49=7²; х=(-9-7)/2=-8; х=(-9+7)/2=-1 _____________
---------------------------(-8)--------------------------------------------(-1)----------------------------------
_______ + _____________________ - ____________________ + _______
х∈(-∞;-8]∪[-1;+∞)