设A=2x²-3xy+y²-x+2y,B=4x²-6xy+2y²-3x-y,若|

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| 设A=2x²-3xy+y²-x+2y ,B=4x²-6xy+2y²+3x-y . x/y=2,求分式x²-xy+3y²/x²+xy+6y² |x+2y+3|+(2x+y)²=0求x²-xy+y² 已知x/y=3,求x²+2xy-3y²/x²-2xy+y² 已知x/y=3,求x²+2xy-3y²/x²-xy+y²的值 已知X²-5XY+6Y²=0,求(X²+3XY)\2Y²的值 已知A=4x²-5xy+y²,B=x²+3xy-5y² 求:A-2B的值 2道数学集合设A=｛x-y,x+y,xy｝,B=｛x²+y²,x²-y²,0｝, 计算:(1).(-2xy²)*(3x²y)² 若x/y=2,求分式(x²-xy+3y²)/(x²+xy+6y²)的值