圆C：x^2+y^2+2x-4y+3=0,若不过原点的直线l与圆C相切,在x,y轴上截距相等,求直线l.从圆C外一点P(x,y)向...圆C：x^2+y^2+2x-4y+3=0,若不过原点的直线l与圆C相切,在x,y轴上截距相等,求直线l.从圆C外一点P(x,y)

如果A={（x,y）|x,y+2>0},B={（x,y）|2x+3y-6>0},C={（x,y）|x-4 (x-y) (x-2y)+(x+2y) (x-3y)-2(x-3y) (x-4y)= 已知圆C：x²+y²－2x－4y－3=0,直线L：y... x-y/x-x+y/y-(x+y)(x-y)/y² y/x=2 已知点P(x,y）是圆C：x^2+y^2+4x+3=0上任意一点,求y/x的取值范围. 圆x²+y²-x+2y=0关于直线x-y+1=0对称的圆的方程是A、x²+y²+4x-3y+5=0B、x²+y²+4x+3y+5=0C、x²+y²-4x-3y+5=0D、x²+y²+4x+3y-5=0 曲线C：2x^+y^-x+2y-3=0关于y轴对称 解微分方程（x+y）dx+(3x+3y-4)dy=0答案x+3y+2ln|x+y-2|=c 已知实数x,y满足x^2+y^2-6x-8y+21=0,若4x+3y+c 3(x+y)+2(x-y)=36 4(x+y)-5(x-y)=2 （x+y）/2- x-y/2=6 3(x+y)=4(x-y) x+y/3+x-y/2=6 4(x+y)-2(x-y)=40 x*x+2x+y*y-4y+5=0 x= y= 2（x+y)-3(x-y)=3 ,4(x+y)+3(x-y)=15 {4x-3y-10=0 3x-2y=0,{3x-4(x-y)=2 2x-3y=1,{2(x+y)-(x-y)=3 (x+y)-2(x-y)=1 {3(x+y)-4(x-y)=4 {x+y/2 + x-y/6=1 x+y/2+x-y/3=6,4(x+y)-3(x-y)=-20 {(x+y)/2+(x-y)/3=6 4(x+y)-3(x-y)=-20