3x²-3x-6=03(x²-x-2)=03(x+1)(x-2)=0x1=-1,x2=2x²+2x-35=0(x+7)(x-5)=0x1=-7,x2=52x²-4x-1=0x={-(-4)±√[(-4)²-4×2×(-1)]}/(2×2)x=(2±√6)/2x1=(2+6)/2,x2=(2-√6)/2