2log5=p 3log3=q nilai 13log20

²log5 = p
³log5 = q

15log20 = ²log20/²log15
= ²log(4x5)/²log(3x5)
= (²log2² + ²log5)/(²log3 + ²log5)
= (2 + p)/(p/q + p)
= (2+p)/(pq+p)/q
= q(2+p)/(pq+p)
= (2q + PQ)/(PQ + p)