Question

化简求值[xy(1-x)-2x(y-½)]*2x^3y^2+2x^4y^3（x+1）其中x=-1,y=½

Answer 1

[xy(1-x)-2x(y-½)]*2x^3y^2+2x^4y^3（x+1）
=(xy-x²y-2xy+x)×2x³y²+2x^5y³+2x^4y³
=-2x^4y³-2x^5y³+2x^4y²+2x^5y³+2x^4y³
=2x^4y²
当x=-1,y=1/2时
原式=2×(-1)^4(1/2)²=1/2

追问

过程正确吗

Answer 2

原式=(xy-x²y-2xy+x)*2x³y²+2x^5y³+2x^4y³
=-x^4y³-2x^5y³+2x^4y²+2x^5y³+2x^4y³
=x^4y³+2x^4y²
=1/8+1/4
=3/8

Answer 3

[xy(1-x)-2x(y-1/2)]*2x^3y^2+2x^4y^3(x+1)=[xy-x^2y-2xy+x]*2x^3y^2+2x^5y^3+2x^4y^3=[-xy-x^2y+x]*2x^3y^2+2x^5y^3+2x^4y^3=-2x^4y^3-2x^6y^3+2x^4y^2+2x^5y^3+2x^4y^3=2x^5y^3+2x^4y^3-2x^6y^3=2x^4y(xy^2+y^2-x^2y^2)
当x=-1，y=1/2时，原式=2*1*1/2（-1*1/4+1/4-1*1/4）=-1/4