(1)原式=-22x2y4?3x2y÷x3y4=-12x4y5÷x3y4=-12xy(2)原式=4x2-6x+2xy-3y-2xy+2y=4x2-6x-y(3)原式=3(m2+2m+1)-5(m2-1)+2(m2-2m+1)=3m2+6m+3-5m2+5+2m2-4m+2=2m+10(4)原式=-(2x2y-x3y2- 1 2 xy3)×2x-1y-1=-2x2y×2x-1y-1+x3y2×2x-1y-1+ 1 2 xy3×2x-1y-1=-4x+2x2y+y2