7x+3y＝5 -5x+6y＝-19

(3x-4y)(5x-4y)-(7x-8y)(6y-5x) 化简下列各式,并求值:3(x-y)²-7(x-y)+8(x-y)²+6(x-y) 其中x=2,y化简下列各式,并求值:3(x-y)²-7(x-y)+8(x-y)²+6(x-y)其中x=2,y＝5 6x²y+2xy-3x²y²-7x-5yx-4y²x²-6x²y＝ 7x+3y＝5 -5x+6y＝-19 若(X×X+Y×Y)(X×X+Y×Y-5)=36,则X×X+Y×Y＝ ｛y＝3x-7｛5x+2y＝8｛x-2y＝3｛2y+x＝-1｛2y-x＝6｛2x+y＝8 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? 2分之x+y+3分之x-y＝1又6分之5 4(x+y)-5(x-y)=7 方程组的解 [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 3x+5y-(x+y)=6 2(x+y)-3x=-7 把(x-y)看作一个整体,化解:5(x-y)+2(x-y)-4(x-y)= 3(x-y)把(x-y)看作一个整体,化解:5(x-y)+2(x-y)-4(x-y)=3(x-y)²-4(x-y)+7(x-y)-6(x-y)²= 4.4x+6y=54 9x+2y=87 5.2x+y=7 2x+5y=19 6.x+24.4x+6y=54 9x+2y=87 5.2x+y=7 2x+5y=19 6.x+2y=21 3x+5y=56 x²-y²+4x+6y-5＝ {6(x-y)-7(x+y)=21 {2(x-y)-5(x+y)=-1 2(2x+3y)(3x+2y)-(6x-y)(2x-5y) 化简:3(x-y)²-7(x-y)+ 2(x-y)²+5(x-y) （x+y）^6/(x+y)^4-(x-y)^5/(x-y)^3 化简 .. 因式分解x次方-y次方+5x-y+6【x-y+2】【x+y+3】