* 1.|3x-y+5|+(2x+3y-4)²=0,则x= y= 2.{x=3y=5 3y=8-2y
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
(4x-2y-z)-{5x[8y-2y-(x+y)]-x+(3y-10z)]=? kuai
数学题……555{(3x+y)(3x-y)-(x-5y)(5x-y)-(x-2y)²÷(-4x),x=-2.y
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
化简[(3x+4y)^2-(2x+y)(2x-y)+(-x+y)(5x-y)]除以-2y,其中x=-1,y=1
6(x-y)-2(x+y)=14 3(x-y)+(x+y)=5
若3x-5y=0,则x+y/x=(),x-y/y=(),2x-3y/2x+3y=( )
【2(x-y)^3-8(x-y)^2(x+y)+6y(x-y)^2】/2(x-y)^2=
微分方程(1)(y'')^2+5y'-y+x=0;(2)y''+5y'+4y^2-8x=0;(3)(3x+2y)dx+(
已知x=1/3,y=-1/2,求代数式x-(x+y)+(x+2y)-(x+3y)+(x+4y)-(x+5y)+...-(
已知X-Y/X+Y=3,求代数式2(x-y)/X+Y-3X+Y/X+Y