Х²-6х-27>0
D/4=9-27=36=+-6²
x1=3+6=9
x2=3-6= - 3
(-∞; -3) (9; ∞)
17x-6x²-5<0<br>-6x²+17x-5<0<br>D=289-120=169=+-13²
x1=( -17+13)/(-12)=1/3
x2=( -17-13)/(-12)=2 1/2
(-∞; 1/3) (2 1/2; ∞)
x²-6x+8<0<br>D/4=9-8=+-1
x1=3-1=2
x2=3+1=4
(-∞; 2) (4; ∞)
x²-5x+6>0
D=25-24=+-1
x1=(5+1)/2=3
x2=(5-1)/2=2
(-∞; 2) (3; ∞)