Question #c11ad

1 Answer
Dec 26, 2016

see below

Explanation:

concepts applied

  • \log_a(b^c)\rArrc\log_a(b)loga(bc)cloga(b)
  • \log_a(b)=x\leftrightarrowa^x=bloga(b)=xax=b

if referring to the log as base 10 log, log_10xlog10x:
(\log_10(225))/(\log_10(25))log10(225)log10(25)

then
numerator: \log_10(15^2)\rArr2\log_10(15)log10(152)2log10(15)
denominator: \log_10(5^2)\rArr2\log_10(5)log10(52)2log10(5)

becomes
(2\log_10(25))/(2\log_10(5))2log10(25)2log10(5)
the 2's cancel, which leaves you with (\log_10(25))/(\log_10(5))log10(25)log10(5)

simplify and you get your answer.


if referring to the log as natural log, log_exlogex or lnxlnx:
(\log_e(225))/(\log_e(25))\rArr(\ln(225))/(\ln(25))loge(225)loge(25)ln(225)ln(25)

then
numerator: \ln(15^2)\rArr2\ln(15)ln(152)2ln(15)
denominator: \ln(5^2)\rArr2\ln(5)ln(52)2ln(5)

becomes
(2\ln(25))/(2\ln(5))2ln(25)2ln(5)
the 2's cancel, which leaves you with (\ln(25))/(\ln(5))ln(25)ln(5)

simplify and you get your answer.