Theory:

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\(m\) and \(n\) are any two non-parallel lines and \(l\) is another line intersecting them at \(A\) and \(B\).
 
Such intersecting line (\(l\)) is called as transversal line.
 
 
A transversal line is a line that intersects  two lines at distinct points.
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The line \(l\) is not a transversal to the lines \(m\) and \(n\), but it is a transversal to the pair of lines \(m\) and \(o\), \(n\) and \(o\).
 
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Line \(l\) does not intersect the lines \(m\) and \(n\) at distinct points. So, it is not a transversal line.