3：4：5＝4X：25－6X－4Y：5Y怎么算

(3x-4y)(5x-4y)-(7x-8y)(6y-5x) （x+y）^6/(x+y)^4-(x-y)^5/(x-y)^3 化简 .. 已知X＝11Y,（X－2）*3＝Y,（X－4）*5＝Y,（X－6）*7＝Y,（X－8）*9＝Y ,求X、Y各是多少? 因式分解(x-2y)(x-3y)+(x-4y)(x-5y)+（x-3y)(x-5y)+(x-2y)(x-4y) 3x＝4y,则x/y=( ),y－x/y＝( ) 5(x-y)^3*[-6/25(y-x)^3][-2/3(y-x^4]= 因式分解[(4x+y)(4x－y)－(2x－3y)2－2y(2x-5y)]÷4x 因式分解 x-xy+3y-3x 2x+xy-y-4x+5y-6 6x－3y＝-3,5x-9y＝4 【(4x-3y)(4x+3y)-(2x-3y)(5x+3y)]除以6x 化简(x+y)-(2x+y/2)-(3x+y/6)-(4x+y/12)-(5x+y/20)-……-(10x+y/90) （5x-3y)(3y+5x)-(4y-3x)(3x-4y) 5/4(x+y)(-x-y)^3*[-4/3(x-y)]*[-3/5(y-x)^2] （5x+3y)(3y-5x)-(4x-y)(4y+x)= 5x^3y(x-y)^3-10x^4y^3(y-x)^2因式分解 5x^3y(x-y)^3-10x^4y^3(y-x)^2 5X^3Y(X-Y)-10X^4Y^3(Y-X)^2因式分解 4(x-y)-3(x-y)=9 5(x-y)+2(x-y)=11