Let u>0u>0u>0, v>0v>0v>0, a>0 a>0\,a>0 and a≠1a\ne1a=1.
Starting from the definition of a logarithm, prove that loga(u2v3)=2logau−3logav\log_a\left(\dfrac{u^2}{v^3}\right)=2\log_a u-3\log_a vloga(v3u2)=2logau−3logav.
Your proof must not quote any logarithm law.