1.(2018湖北稳派教育二联,3)若直线l1:x+ay+6=0与l2:(a-2)x+3y+2a=0平行,则l1与l2之间的距离为 ( )
A. B.4
C. D.2
2.直线y=3x绕原点逆时针旋转90°,再向右平移1个单位长度,所得到的直线为( )
A.y=-x+ B.y=-x+1
C.y=3x-3 D.y=x+1
3.直线ax+4y-2=0与直线2x-5y+b=0垂直,垂足为(1,c),则a+b+c=( )
A.-2 B.-4
C.-6 D.-8
4.三条直线ax+2y+8=0,4x+3y=10,2x-y=10相交于一点,则a的值是( )
A.-2 B.-1
C.0 D.1
5.已知平行四边形ABCD的一条对角线固定在A(3,-1),C(2,-3)两点,点D在直线3x-y+1=0上移动,则点B的轨迹方程为( )
A.3x-y-20=0 B.3x-y-10=0
C.3x-y-9=0 D.3x-y-12=0
6.直线x-2y+1=0关于直线x=1对称的直线方程是 ( )
A.x+2y-1=0 B.2x+y-1=0
C.2x+y-3=0 D.x+2y-3=0
