化简:(1)(x²-y²)-3(2x²-3y²)
先化简再求值:(x-2y)²-(x+2y)(x-2y)-(x-3y)(x-y).其中x²+9y
化简 (x+y)(x²-xy+y²) ; 3(2x-1)(x+6)-5(x-3)(x+6)
计算3x[xy-2x(1/y-x/3]+3y(x²-y²)
(3x-y)²-2x(4x-5y)-(x+2y)²
化简 3(X-Y)²-4(X-Y)+7(X-Y)-6(X-Y)²
1、化简:5(x-y)²+(2x+y)-2(x-y)²-3(2x+y)-3(x-y)²
先化简,在求值:(x-y)²+(3x-2y)(2x+y)-x(6x-y)
(1):(x+2y)²-(x+y)(3x-y) (2):(2x+3y)²-(2x-3y)²
(1)已知x+y=6,x²-y²=5,求x-y的值(2)若x+y=3,x²+y²
(x+y)和(x-y)各看成一个整体,合并同类项2(x+y)-3(x-y)²+3(x+y)+4(x-y)
化简:(2x-y)²-4(x-y)(x+y)
已知x-y=1,y≠0,求{(x+2y)²+(2x+y)(x+4y)-3(x+y)(x-y)}÷y的值.