Question

Last but not least, thank you for your efforts <3

Answer 1

L = (P - 2W) / 2

Explanation:

P = 2L + 2W

P = 2L + 2W - 2W

P - 2W = 2L

(P - 2W) / 2 = 2L / 2

(P - 2W) / 2 = L

L = (P - 2W) / 2