(3x-4y)^2-(3x+y)^2(x+1/2y-3)(x-1/2y+3)已知x+y=5,X^2-Y^2=15,求x-y的值是 x加二分之一y减去3你们的答案我看不懂~好多不一样的%……

(x-y) (x-2y)+(x+2y) (x-3y)-2(x-3y) (x-4y)= x(x-y)2-(y-x)3 (x+3y-4)(2x-y) 计算（2x-3y)(x+4y)-(3x+y)(x-2y)（2x-3y)(x+4y)-(3x+y)(x-2y) 因式分解(x-2y)(x-3y)+(x-4y)(x-5y)+（x-3y)(x-5y)+(x-2y)(x-4y) x²/xy-x/y 3x/4x+y - x-2y/4x+y (1-y/y+x)÷x/y²-x² [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 (2x+y)(2x-3y)+x(2y+y) 2a(x-y)-4b(x-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 (2x-y)(2x+y)-2(3x-4y)(4y+3x) (3x-y)(y+3x)-2(4x-3y)(4x+3y) x^4+x^3y+x^2*y^2+y^3x+y^4分解因式 (x-3y)(y+2x)-(4y-3x)(3x+4y)计算