can anyone help me pls

Answer:
4x - 5 ft
Step-by-step explanation:
Perimeter = 4 × side
16x - 20 = 4 × side
(16x - 20)/4 = side
4x - 5 = side
Answer:
[tex]perimeter = 2(l + b) \\ 16x - 20 = 2(2l)(square \: so \: l = b) \\ 16x - 20 = 4l \\ l =( 16x - 20 )\div 4 = 4x - 5 \\ thank \: you[/tex]