若圆C:x^2+y^2+x-6y+3+0上有两个点P和Q关于直线kx-y+4+0对称,则k=?如有过程加到20金币。

如果A={（x,y）|x,y+2>0},B={（x,y）|2x+3y-6>0},C={（x,y）|x-4 【2(x-y)(x-y)(x-y)-8(x-y)(x-y)(x+y)+6y(x-y)(x-y)]/2(x-y)(x-y) 若y:3=2:x,下列等式(x,y不等于0),成立的是（） A.3x=2y B.x=y/6 C.X=6/Y D.=2X=3Y 已知实数x,y满足x^2+y^2-6x-8y+21=0,若4x+3y+c [2(x-y)^5-8(x-y)^2(x+y)+6y(x-y)^2]÷2(x-y)^2[2(x-y)^3-8(x-y)^2(x+y)+6y(x-y)^2]÷2(x-y)^2 3y/x*x-y*y+x/x*x-2xy+y*y+6y*y/x*x*x-x*x*y-xy*y+y*y*y等于多少? 因式分解3x^2(x-y)+6x(y-x) 【2(x-y)^3-8(x-y)^2(x+y)+6y(x-y)^2】/2(x-y)^2= 曲线C：2x^+y^-x+2y-3=0关于y轴对称 a(x-y)(x+y)-b(y-x)(x+y)-c(x-y)^2(y+x)提取公因式 分式x/2x+6y,3/x-3y,x+y/x²-9y² 的最简公分母是( ) .A.(x+3y)(x-3y) B.2(x+3y)(x-3y) C.3(x+3y)(x-3y) D.2(x-3y)² 设圆C:x^2+y^2+4x-6y=0,若圆C关于直线l:a*(x-2y)-(2-a)*(2x+3y-4)=0对称,求实数a的值 设圆C:x^2+y^2+4x-6y=0,若圆C关于直线l:a*(x-2y)-(2-a)*(2x+3y-4)=0对称,求实数a 已知x,y属于R,且(2^x)+(3^y)＞(2^-y)+(3^-x),正确的是（） A.X+Y＞0 B.X+Y＜0 C.X-Y＞0 D.X-Y＜0 x(x-y)2-(y-x)3 {x+y=1 ,xy=-6{x(2x-3)=0,y=x²-1{(3x+4y-3)(3x+4y+3)=0,3x+2y=5{(x-y+2)(x+y)=0,x²+y²=8{(x+y)((x+y-1)=0,(x-y)(x-y-1)=0 x^2+4y^2-6x+4y+10=0,求x^4-y^4/(x+2y)(x-2y)*x+2y/xy^2+y^3除以（x^2+y^2/y)^2的值 x(y-x)-y(x-y) (-3xy)*5c^2Y+6x^2(7/2xy^2-2y^2)