圆C:x^2+y^2+2x-6y-15=0与直线l:(1+3m)x+(3-2m)y+4m-17=0的交点个数是?a,b,c分别指什么?圆的半径应该是根号5吧

x-y/x-x+y/y-(x+y)(x-y)/y² y/x=2 【2(x-y)(x-y)(x-y)-8(x-y)(x-y)(x+y)+6y(x-y)(x-y)]/2(x-y)(x-y) 如果A={（x,y）|x,y+2>0},B={（x,y）|2x+3y-6>0},C={（x,y）|x-4 a(x-y)(x+y)-b(y-x)(x+y)-c(x-y)^2(y+x)提取公因式 【2(x-y)^3-8(x-y)^2(x+y)+6y(x-y)^2】/2(x-y)^2= x^2+y^2=15,x+y=7,x＞y,求x-y x+y/2+x-y/6=5 2(x+y)-3(x-y)=-2 [(2x-y)(2x+y)+y(y-6x)]÷2x=? （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 2（x+y)-3(x-y)=3 ,4(x+y)+3(x-y)=15 2(x+y)-3(x-y)=1 6(x+y)+(x-y)=51 {3(x+y)-4(x-y)=4 {x+y/2 + x-y/6=1 {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 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 4(x+y)-3(x-y)=-20,2/x+y+3/x-y=6