3x+2y=5x+2,2（3x+2y）=11x+17

已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y) 3(x+y)-4(x-y)=11,2(x-y)+5(x+y)=27 先化简再求值(x-y)(x+y)-(x-2y) 的完全平方+x(3x-5y)-(x-y)(x-2y),其中x=1/2 y 6(x-y)-2(x+y)=14 3(x-y)+(x+y)=5 已知X-Y/X+Y=3,求代数式2(x-y)/X+Y-3X+Y/X+Y 若3x-5y=0,则x+y/x=（）,x-y/y=（）,2x-3y/2x+3y=( ) 已知x=1/3,y=-1/2,求代数式x-(x+y)+(x+2y)-(x+3y)+(x+4y)-(x+5y)+...-( 数学题……555{(3x+y)(3x-y)-(x-5y)(5x-y)-(x-2y)²÷(-4x),x=-2.y 已知x=2,y=3,求代数式（x-y）*（x-y）^3*(x-y)^5*……*(x-y)^11 化简[(3x+4y)^2-(2x+y)(2x-y)+(-x+y)(5x-y)]除以-2y,其中x=-1,y=1 【2(x-y)^3-8(x-y)^2(x+y)+6y(x-y)^2】/2(x-y)^2= 5x=3y,(2x+y)的平方=5x(x+y)+9