直线(1+3m)x+(3-2m)y+8m-12=0(m∈R)与圆x2+y2-2x-6y+1=0的公共点个数是(  ) A.1 B.0或2 C.2 D.1或2

问题描述:

直线(1+3m)x+(3-2m)y+8m-12=0(m∈R)与圆x2+y2-2x-6y+1=0的公共点个数是(  )
A. 1
B. 0或2
C. 2
D. 1或2

直线(1+3m)x+(3-2m)y+8m-12=0可化为
(3x-2y+8)m+(x+3y-12)=0
令3x-2y+8=0且x+3y-12=0
解得x=0,y=4,
即直线(1+3m)x+(3-2m)y+8m-12=0恒过(0,4)点
将(0,4)点代入圆x2+y2-2x-6y+1=0得
x2+y2-2x-6y+1=-7<0
即该点在圆内,故直线(1+3m)x+(3-2m)y+8m-12=0(m∈R)与圆x2+y2-2x-6y+1=0的公共点个数2个
故选C