**Contoh 2:**

Cari nilai bagi setiap yang berikut.

$\begin{array}{l}\text{(a)}{\mathrm{log}}_{2}7+{\mathrm{log}}_{2}12+{\mathrm{log}}_{2}21\\ \text{(b)3}{\mathrm{log}}_{10}5+2{\mathrm{log}}_{10}2-{\mathrm{log}}_{10}5\\ \text{(c)2}{\mathrm{log}}_{10}3-{\mathrm{log}}_{10}3+{\mathrm{log}}_{10}3\frac{1}{3}\\ \text{(d)}{\mathrm{log}}_{3}3p+{\mathrm{log}}_{3}3q-{\mathrm{log}}_{3}pq\end{array}$

*Penyelesaian:*