若x+y=6,x-y=4则y2-x2

若x2+4x+y2-6y+13=0则x=?y=? 若x+y=6,x-y=4则y2-x2 若x2+y2=4,则x-y最大值 如题：若4x=5y(y≠0),则x2-y2/y2=?. 若x2+4x+y2-6y+13=0,则(x+2y)(x-2y)的值为---------- 已知x2+4y2+x2y2+1=6xy,则(x4-y4)/(2x2+xy-y2)*(2x-y)/(xy-y2)/(x2+y2/y)2= x2-2xy+y2=4 x2+y2-x-y=6 解不等式x2-2xy+y2=4 x2+y2-x-y=6 解不等式 若f(x+y,x-y)=x2-y2,则f(x,y)=, 若x2-y2=6,x+y=3,则x-y= 若x+y=6,x2-y2=48,则x-y=_____ 若x2+y2-2x+4y+5=0 则x= y= 若X2+2X+Y2-6Y+10=0,则X+Y=? 若x-y/x+y=2,则x2+2xy+y2/4xy=多少 已知x2+y2-2x-6y+10=0,则4/(y+1/x)= 若x2-6x+y2+4y+13=0,求x+y 若实数x、y满足x2+y2+4x-6y+4=0,则根号下（x2+y2）的最大值是 x2+y2=4则4x+3y最大值 x2-4x+y2+6y+13=0,