Question

Rewrite this sum of two logarithms as a single logarithm. log 20 + log7x = log7

Answer 1

To solve this question, we need to know a particular law of logarithm. This law is stated below:

$\log _ab+\log _ac=\log _a(b\times c)$

From the question, it is obvious that:

a = 7

b = 20

x = c

Therefore, we can re-write the question as:

$\begin{gathered} \log _720+\log _7x=\log _a(20\times x) \\ \\ \therefore\log _a(20x) \end{gathered}$