若丨2x-5丨+(2x-5y+20)^2=0,求代数式(-2x^2)-2x(5y-2x)=3y(6x-5y)-3y(4x-5y)的值

若丨2x-5丨+(2x-5y+20)^2=0,求代数式(-2x^2)-2x(5y-2x)=3y(6x-5y)-3y(4x-5y)的值 5x(x-y)+2y(x-y) 化简:5(x-y)+2(x+y)-3(x-y) 已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y) (2x+y)²+(x+3y)(x-3y)-x(5x+8y)因式分解 （X+2Y)(5X-2Y) (x+2y)(5x-2y) 4x+2y-5x-y (2x-3y)-(5x-y) (2X-3y)-(5x-y) (x-y)^2+5(x-y)-14 (2x-5y)(3x+y) 因式分解(x-2y)(x-3y)+(x-4y)(x-5y)+（x-3y)(x-5y)+(x-2y)(x-4y) 化简(x+y)-(2x+y/2)-(3x+y/6)-(4x+y/12)-(5x+y/20)-……-(10x+y/90) [(x+2y)(x-2y)-(2x-y)^2+(3x-y))2x-5y)]/(-x)我急用 [(x+2y)(x-2y)-(2x-y)²+(3x-y(2x-5y)]/(-x)的解答 [2(x-y)^5-8(x-y)^2(x+y)+6y(x-y)^2]÷2(x-y)^2[2(x-y)^3-8(x-y)^2(x+y)+6y(x-y)^2]÷2(x-y)^2 化简(4x-2y)-[5x-(8y-2x-x-y)]+x