3X+8Y=51 X+6Y=21 问X=?Y=?

3X+8Y=51 X+6Y=21 问X=?Y=? 已知x-y=3,x+y=8,问x^2 -y^2=? 【2(x-y)^3-8(x-y)^2(x+y)+6y(x-y)^2】/2(x-y)^2= 2(x+y)-3(x-y)=1 6(x+y)+(x-y)=51 7x+6y=21 3x+4y=12 问x和y是多少? x@y=(x+y)除以2,X#Y=3X-Y除以2 问：(9@x）#30=6,求x的值. 8x+10y=1252 x+y=143 问x=?y=? x+y=3,xy=1,问：y分之x+x分之y= x+x+y+y+y=21 ,x+x+y+y+y+y+y=27 ,x ,y=? x+x+y+y+y=21 ,x+x+y+y+y+y+y=27 ,x ,y=? 已知x.x+y.y-6x-8y+25=0,求3x.x+5y的值 x-y/x-x+y/y-(x+y)(x-y)/y² y/x=2 2x+y=17,x-2y=1问x=多少.3x+2y=8,6x+3y=15问x=多少 （x+y-5)*（x+y-5)+（x-y+3)=0 x*x-y*y 已知:3x-5y=0,求x/y,x-y/y,x-y/x {6(x-y)-7(x+y)=21 {2(x-y)-5(x+y)=-1 推倒公式:(x+y)(x*x-3x+y*y)=x*x*x+y*y*y怎么做. x+y/2+x-y/3=6,4(x+y)-3(x-y)=-20