3x+2y/4=x+5y/-3=2x+y+2/5

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 化简[(3x+4y)^2-(2x+y)(2x-y)+(-x+y)(5x-y)]除以-2y,其中x=-1,y=1 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 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 6(x-y)-2(x+y)=14 3(x-y)+(x+y)=5 (4x-2y-z)-{5x[8y-2y-(x+y)]-x+(3y-10z)]=? kuai 3x-2y=1 4x-5y 3x+3y+2x-2y=36 4x+4y-5x-5y=2 数学(x-y)^5*(y-x)^3*(x-y)^2 4x-2y-6y*-y-3x+5y* *=2 就是平方