how do i solve this question

Answer:
[tex]a\frac{c}{8\pi b}[/tex]
Step-by-step explanation:
Divide both sides by [tex]8\pi b[/tex]
[tex]\frac{8\pi ab}{8\pi b} =\frac{c}{8\pi b}[/tex]
Simplify:
[tex]a\frac{c}{8\pi b}[/tex] ; [tex]a\frac{c}{8\pi b}; b\neq 0[/tex]