(1)=-(1/3)a^2b^3 + a^2b^2 - (2/3)ab^2(2)原式=2x^4 - 2x^3 + 2x^2 - 2x^4 + 10x^3 - 2x^2=8x^3=8×(-1/2)^3=8×(-1/8)=-1
