Решите неравенство:

1) (x-4) (x+5) >0

2) (x-3) (x-8) ≤0

1) (x-4) (x+5) >0

x²-4x+5x-20>0

x²+x-20>0

D=1-4 * (-20) = 1+80=81=9²

x₁ = (-1-9) / 2=-10/2=-5

x₂ = (-1+9) / 2=8/2=4

ответ (-5:4)

(x-3) (x-8) ≤0

x²-3x-8x+24≤0

x²-11x+24≤0

D = (-11) ²-4*24=121-72=49=7²

x = (11-7) / 2=4/2=2

x = (11+7) / 2=18/2=9

Ответ [2:9]