(x+3y)^2*(x-3y)^2 和 1995^2x2005^2 的计算. 过程要明确哈`. 急需`` thanks谢谢哦.

x(x-y)2-(y-x)3 [2/3x-2/x+y(x+y/3x-x-y)]/x-y/x 化简：{2/3x-2/(x+y)[(x+y)/3x-x-y]}/(x+y)/x 计算2/3x-2/x+y(x+y/3x-x-y)/x-y/x 化简3x-2/(x+y)[(x+y)/3x-x-y]÷(x-y)/x 5X+Y=3 X+5Y=2 求x和y.5X+Y=3X+5Y=2求x和y. [(3x+y)(x-y)-(2x+3y)(x-y)]*(x-y) 计算：x+2y/x-y+2x/y-x-3y/x-y 化简:(x-3y)(x+y)-(x-2y)(x+2y)-(x-y)平方 先化简再求值{(x-y)(x+y)-(x+y)(x-2y)}/y 其中xy的值是代数式{(3x-2y-7)^2+|2x+3y先化简再求值{(x-y)(x+y)-(x+y)(x-2y)}/y 其中x和y的值是代数式{(3x-2y-7)^2+|2x+3y+4|}^0无意义 x+y=1 5x-2y=8 3x-y=7 2x-y=3x表示y和用y表示x (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)² 2X(2X-3Y)-3Y(X+Y) (-2x y)^2-(3y-x)(-x-3y) （x+2y)^2-(x+y)(3x-y) 计算(x+y)(x+y)^2(-x-y)^3 化简:5(x-y)+2(x+y)-3(x-y) 3x(x-y)+2y(x-y) 计算