(3y-6)(-y) (-3x)(4x²-4/3x+1) (-xy)(2x-5y-1) 5x(2x+3)+x(

(3y-6)(-y) (-3x)(4x²-4/3x+1) (-xy)(2x-5y-1) 5x(2x+3)+x( 设A=2x²-3xy+y²-x+2y,B=4x²-6xy+2y²+3x-y.若x [(x+2y)²-（x+y)(3x-y)-5y²]÷(2x),其中x,y满足x²+4x+y 试找出多项式3x²y-4xy²-3+5x²y+2xy²+5x的三次方y+1中的同 越快越好（1）(xy²+3)(xy²+3)-2x(-x+y)（2）(x+2)(x²+4)( 已知实数x、y满足5x²-3xy+1/2y²-2x+1/2y+1/4=0 求x、y的值 化简,并求值2(x-2y)²-4（x+3y)(x-3y)-2(x-y).(y+x)-5(-x-1)² 已知x/3y=y/2x-5y=6x-5y/x,则4x²-5xy+6y²/x²-2xy+3y 1、(-3x-4y)·( )=9x²-16y² 2、如果x+y=6,xy=7,那么x²+y x^8-x^7y+x^6y^2-x^5y^3+x^4y^4-x^3y^5+x^2y^-xy^7+y^8 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 .