直线L1：<img border="0" alt="" src="https://tuku.weimei168.com/uploads/upimg/20251103/23817746_0.png">与L2：<img border="0" alt="" src="https://tuku.weimei168.com/uploads/upimg/20251103/23817746_0_1.png">之间的关系是（　　）。