## Precalculus (6th Edition)

$f=\dfrac{AB(p+1)}{24}$
Multiply $B(p+1)$ to both sides of the equation to obtain: $$\require{cancel} \\A(B(p+1))=\dfrac{24f}{B(p+1)} \cdot B(p+1) \\\\AB(p+1)=\dfrac{24f}{\cancel{B(p+1)}} \cdot \cancel{B(p+1)} \\AB(p+1)=24f$$ Divide $24$ to both sides to obtain: $$\dfrac{AB(p+1)}{24}=\dfrac{24f}{24} \\\dfrac{AB(p+1)}{24}=f$$