Diketahui 2log 5 =p dan 5log 7=q Maka 5log 28=

[tex]^{5} log 28 = ^{5} log( {2}^{2} \times 7) \\ = ^{5} log {2}^{2} + ^{5} log7 \\ = 2 \times ^{5} log2 + ^{5} log 7 \\ = \frac{2}{ ^{2}log5 } + ^{5} log7 \\ = \frac{2}{p} + q \\ = \frac{2 + pq}{p} [/tex]