Answer:
LN = 13 units.
Explanation:
If LMNP is a rectangle, then LN and MP are the two diagonals of the rectangle and they are equal.
Now, given that LN = 7x - 8 and MP = 4x + 1
So, 7x - 8 = 4x + 1
⇒ 3x = 9
⇒ x = 3
Therefore, LN = 7x - 8 = 7(3) - 8 = 13 units. (Answer)