Question

Answer the question for the function f(x) = log10 x Find the ratio of a to b when f(a) = 5 + f(b).

Answer 1

 $f(x)=lgx\\ lga=5+lgb\\ lg(\frac{a}{b})=5\\ \frac{a}{b}=10^5$

Answer 2

$f(a)=lg(a) \\ f(b)=lg(b)\\lg(a)=5+lg(b) \\ lg(a)-lg(b)=5 \\ lg \frac{a}{b} =5 \\ \frac{a}{b} =10^5$