1)2x-3x-3>2+x
2x-3x-x>2+3
-2x>5
x>-2.5
2)D=9-4*(-1)*(-2)=9-8=1
x1,2= -3+_1:-2
x1=2
x2=1
3)x^2+2x+6x+12<0
x^2+8x+12=0
D=64-4*12=16
x1,2= -2+_4:2
x1=-3
x2=1
4)x^2<49
x<+_7
5)x^2(3x-2)(x-8)<0
x^2*3x^2-24x-2x+16<0
4x^2-26x+16
-----------------------------------------