Help please I’m having trouble with this problem

Answer:
[tex]\sf length = 8b+2[/tex]
Explanation:
Given:
using the formula:
[tex]\hookrightarrow \sf 64b^2 - 4 = length * (8b - 2)[/tex]
[tex]\hookrightarrow \sf \dfrac{64b^2 - 4 }{(8b - 2)} = length[/tex]
[tex]\hookrightarrow \sf length = 8b+2[/tex]