若A=x^3-2xy^2+1,B=x^3+xy^2-3x^y,则多项式2x^3-7xy^2+3x^y+3=( ) A.A

若A=x^3-2xy^2+1,B=x^3+xy^2-3x^y,则多项式2x^3-7xy^2+3x^y+3=( ) A.A x²（x+y)(y-x)-xy(x+y)(x-y) 已知a+b=4,ab=-2,求多项式3a²b+3 已知：A=X*X-3xy+y*y,B=2x*x+xy-3y*3y.求A+B,A-B,A+2B 已知:xy+x=-1,xy-y=-2,求多项式-x-[2y-2(xy+x)的平方+3x]+2[x+(xy-y)的平方]的 已知A=x³-2xy²+1,B=x³=xy²-3x²y.求多项式3A+ A=2x²-3xy+y²-x+2y,B=4x²-6xy+2y²+3x-y,若x= 设A=2x²-3xy+y²-x+2y,B=4x²-6xy+2y²-3x-y,若x 设A=2x²-3xy+y²-x+2y,B=4x²-6xy+2y²+3x-y.若x 已知A=8x^2y-6xy^2-3xy,B=7xy^2-2xy+5x^2y, 已知A=5x^2y-3xy^2+4xy,B=7xy^2-2xy+x^2y. 已知代数式A=2x^3+3xy+2y-1,B=x^2-xy+x-1/2 已知代数式A=2x^2+3xy+2y-1,B=x^2-xy+x-1/2