Question 409004
{{{log(4,x) - log(4,(x+15)) = -1}}}
{{{log(4,x/(x+15)) = -1}}}
{{{x/(x+15) = 4^(-1)}}}
{{{x/(x+15) = 1/4}}}
cross-multiplying:
{{{4x = x+15}}}
{{{3x = 15}}}
{{{x = 5}}}