设直线l1:x+my+6=0和l2:(m-2)x+3y+2m=0,当m=_时l1∥l2;当m=_时l1⊥l2;当m_时l1与l2相交;当m=_时l1与l2重合.
问题描述:
设直线l1:x+my+6=0和l2:(m-2)x+3y+2m=0,当m=______时l1∥l2;当m=______时l1⊥l2;当m______时l1与l2相交;当m=______时l1与l2重合.
答
∵直线l1:x+my+6=0和l2:(m-2)x+3y+2m=0,l1∥l2,∴m-21=3m≠2m6,解得m=-1;∵直线l1:x+my+6=0和l2:(m-2)x+3y+2m=0,l1⊥l2,∴1×(m-2)+3m=0,解得m=12;∵直线l1:x+my+6=0和l2:(m-2)x+3y+2m=0,l1...