2log3 =a 3log5=b nilai dari 30log90

³⁰log 90
= ³log 90 / ³log 30
= (³log (3² . 2 . 5)) / (³log (2 . 3 . 5)
= (³log 3² + ³log 2 + ³log 5) / (³log 2 + ³log 3 + ³log 5)
= (2 + 1/a + b) / (1/a + 1 + b)
= ((2a + ab + 1)/a) / ((a + ab + 1)/2)
= (2a + ab + 1)/(a + ab + 1)

jawaban terlampir :)