10.D11.B解题思路:10.∵3x+y-3=0//6x+my+1=0∴3/1=6/m(系数比值相同)∴m=2∴6x+my+1=6x+2m+1=3x+y+1/2=0(代入化简)∵d=|C1-C2|/√(A^2+B^2)=|-3-1/2|/√(3^2+1^2)=(7/2)/√(10)=(7/20)√1011.两圆心坐标分别为(0,0),(4,-3)∴距离d=5;∵r1=3,r2=4∴|r1-r2|∴两圆相交
