第1个.6xy-3x²-3y² 第二个,4x²(x-y)+y²(y-x)
计算3x[xy-2x(1/y-x/3]+3y(x²-y²)
x²/xy-x/y
急![(3x+y)²-3(3x-y)(x+y)-(x-3y)(x+3y)]÷(2xy)
已知x,y满足x²+y²-4x-6y+13=0,求(- y/x^3)^3÷(- 1/xy)^4.(x
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x²+y²-8x+6y+25=0,求(x-y+4xy/x-y)(x+y-4xy/x+y)
(x-y)²-(3x-3xy+y²)因式分解
x²+xy/(x-4y)(x+y),其中x=4,y=-1
化简 (x+y)(x²-xy+y²) ; 3(2x-1)(x+6)-5(x-3)(x+6)
化简 3(X-Y)²-4(X-Y)+7(X-Y)-6(X-Y)²
3x²y+xy²-[2xy²-4x²y+(x²y-2xy²)