当y-x=5 x^2-y^2+5x+5y+2009=?

当y-x=5 x^2-y^2+5x+5y+2009=? 当y分之x=5分之2时,求x+y分之3x-y 已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y) 2(x-y)=5y,x-y=-5 x-y / 5y= (y-x)^2 / ( ) x+y/2+x-y/6=5 2(x+y)-3(x-y)=-2 解方程组(x+y)(x-2y)=-5 (x-y)(x+2y)=7 3(x+y)+2(x-y)=36 4(x+y)-5(x-y)=2 x*x+2x+y*y-4y+5=0 x= y= 4(x-y)-3(x-y)=9 5(x-y)+2(x-y)=11 3(x+y)-4(x-y)=11,2(x-y)+5(x+y)=27 {6(x-y)-7(x+y)=21 {2(x-y)-5(x+y)=-1 6(x-y)-2(x+y)=14 3(x-y)+(x+y)=5 求(X+Y)(X-Y)(X²+Y²),X=5 Y=2, (x-y)/(x+y)=3求( 3x-2y-1)/(x+y-5) 当x,y满足_____时,分式 x-2y/5x+3y有意义 函数y=5x-10,当x=2时y=?当x=0时y=? 5x(x-y)+2y(x-y)