方程组:2Y-X=X-2Y+20 Y-2X+50=2X-Y X=( ) Y=( )

解方程组(x+y)(x-2y)=-5 (x-y)(x+2y)=7 已知方程组4x+2y=1,20x+8y,求x,y [x(x-y)-y(x-y)+(x+y)(x-y)]÷2x其中x=2012 y=2013 已知X-Y/X+Y=3,求代数式2(x-y)/X+Y-3X+Y/X+Y 已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y) y'-2y=(e^x)-x y'+2y/x=x通解 已知x,y的值满足方程组x+2y=3,x-y=-2,求x/(x-y)²+x²-y²/(x+ 方程组2X-Y=9,X+2Y=A,则X:Y=? 方程组 x+5y+2=06x-7y=16x=y= 方程组x-2y=8,3x-4y=5,x=?,y=? 解方程组X+Y/2=3X-2Y=10+6X+Y/4