6x-1=2x=1/2y²-y-2=0(y-2)(y+1)=0y=2,y=-1(5x²y+5xy-7x)-(4x²y+5xy-7x)=5x²y+5xy-7x-4x²y-5xy+7x=x²y=(1/2)²×2或(1/2)²×(-1)=1/2或-1/4