In straight lines, Lesson about concurrency of three straight lines. I have a doubt. How to understand lamda*L1 + lamda*L2 + lamda*L3=0 where L1, L2 and L2 are straight lines. what is the derivation. if L1, L2 and L3 are non zero numbers, then for any three equations, cant we just saylamda*L1 + lamda*L2 + lamda*L3=0 and they are concurrent. please explain...