已知两条直线l1:2x-y+a=0(a>0),l2:-4x+2y+1=0,若l1与l2间的距离是,则a=... 问题详情:已知两条直线l1:2x-y+a=0(a>0),l2:-4x+2y+1=0,若l1与l2间的距离是,则a=____.【回答】3 知识点:直线与方程题型:填空题...