Решите неравенство -9x-7<7x
Помогиииитее :((

-9х-7<7х
(-9х-7)² < (7x)²
81x² + 126x +49 < 49x²
32x² + 126x +49 < 0
D = 126² - 4*32*49 = 15876 - 6272 = 9604 > 0
√D = √9604 = 98
x1 = (-126+98) 64= -(2468) = -(617)
x2 = (-126 - 98) 64 = -(22468) = -3,5
x ∈ (-∞; -(617]U[-3,5; ∞)