Question

If $l,m,n$ are lines in the same plane such that $l$ intersects $m$ and $n\parallel m$, then show that $l$ intersects $n$ also.

Answer 1

Let if possible l and n be non-intersecting lines.
ln
But $n || m$ [Given]
Therefore lm
l and m are non-intersecting line
But it is given that l and m are intersecting lines.
So, our supposition is wrong. Hence line l intersects line n.