Jika ²log3 = p dan ³log5 = q maka ¹5log20=

Keterangan :
2log3 = p
3log5 = q
2log3 x 3log5 = pq
2log5 = pq
5log2 = 1/pq

5log20 = 5log(2^2 x 5)
= 5log5 + 5log2^2
= 1 + 2 x 5log2
= 1 + 2 x 1/pq
= 1 + 2/pq
= (pq + 2)/pq
Semoga membantu :)