2x平方-3x-6=0解:x²-3/2x=3 x²-3/2x+9/16=3+9/16 (x-3/4)²=57/16 x-3/4=±√57/4 x=3/4±√57/4
2x²-3x-6=02(x²-3x/2-3)=0x²-3x/2-3=0(x-3/4)²-9/16-3=0(x-3/4)²-57/16=0(x-3/4)²=57/16x-3/4=±√57/4x1=(3+√57)/4x2=(3-√57)/4