**5.2a Hukum-hukum Logaritma (Contoh 3)**

**Contoh 3:**

Diberi bahawa log

_{7 }4 = 0.712 dan log_{7 }5 = 0.827, cari nilai bagi setiap yang berikut.$\begin{array}{l}\text{(a)}{\mathrm{log}}_{7}20\\ \text{(b)}{\mathrm{log}}_{7}\text{1}\frac{1}{4}\text{}\\ \text{(c)}{\mathrm{log}}_{7}0.8\text{}\\ \text{(d)}{\mathrm{log}}_{7}28\text{}\\ \text{(e)}{\mathrm{log}}_{7}140\text{}\\ \text{(f)}{\mathrm{log}}_{7}100\text{}\\ \text{(g)}{\mathrm{log}}_{7}0.25\text{}\\ \text{(h)}{\mathrm{log}}_{7}\frac{35}{64}\text{}\end{array}$

*Penyelesaian:*