若圆x^2+y^2=1和圆(x-2)^2+(y-1)^2=r^2(r>0)在其交点处的切线互相垂直,则r的值为?

x-y/x-x+y/y-(x+y)(x-y)/y² y/x=2 (x-2y)(x+y)-2x(-2x-3y)+6x(-x-y),其中x=-1,y=2要讲解和答题 x+y=1 5x-2y=8 3x-y=7 2x-y=3x表示y和用y表示x 方程组2x-(x+y)=-1和x+4(x+y)=22 2x+4y=3 -3x-2y=1 ..求x和y 2x+y=1,25x+2y=-40,求x和y? 解方程组,(x+y)^2-3(x+y)=0和x-y=1 已知X和Y满足3X+4Y=2,X-Y-1/7 (2x-2y)/3-(x-y)=-1和6(x+y)-4(2x-y)=16 方程x(x*x+y*y-1)=0和x*x-(x*x+y*y-1)^2=0表示的图形是? 解方程组3(x+y)-4(x-y)=4和(x+y)/2+(x-y)/6=1kkkkkkkk 若x.y满足x+=4和x-y=2,求xy分之2x-y+1除以-x分之y+y分之x的值 已知x+y=a,2x-y=-2a,求[（x/y-y/x)/(x+y)-x(1/x-1/y)]/[(x+1)/y]的值 若2/x-1/y=3,求[y/x-y/x-y(x-y/x-x+y)]/x-2y/x的值 5X+Y=3 X+5Y=2 求x和y.5X+Y=3X+5Y=2求x和y. x-y=-2 x+y=1.x和y分别等于多少?x-y=-2x+y=1.x和y分别等于多少? 计算 (x+2y)(x-2y)+(x+1)和x(x-1)-(x-31)(x+31) 已知x+2x=2x+y+1=7x-5.求x和y的值