Answer:
See below.
Explanation:
A square has 4 equal sides so the length of one of it's sides
= (40x + 60) / 4
= (10x + 15) cm.
A regular pentagon has 5 equal sides so the length of one of it's sides
= (40x + 60) / 5
= (8x + 10) cm.
So the difference is (10x + 15) - (8x + 12)
= (2x + 3) cm.