Problem description:
Football consists of regular pentagonal leather blocks (black) and regular hexagonal leather blocks (white). Use the number x of regular hexagonal blocks to represent the number y of regular pentagonal blocks, and point out variables and constants. (Hint: Each white leather block is surrounded by three black leather blocks. )
Analysis:
Every black one is connected with five white ones, so if there are Y black ones, there should be 5Y white ones.
And each white one is connected with three black ones, so the white one is only: 5Y/3.
So: X=5Y/3
Y=3X/5
X, y variables
3/5- constant