1.2x²-18=0
(2x-6)(x+3)
2x-6=0 atau x+3=0
2x=6 x=-3
x=6/2
x=3
2.2x²+5x+2=0
(2x+1)(x+2)
2x+1=0 atau x+2=0
2x=-1 x=-2
x=-1/2
x=-0,5
3.(2x+5)(x-9)=11-4x
2x²-18x+5x-45-11+4x=0
2x²-9x-56=0
(2x+7)(x-8)
2x+7=0 atau x-8=0
2x=-7 x=8
x=-7/2
x=-3,5