Question 157745
{{{log(x,16) = -2}}}
write this as 
{{{x^(-2) = 16}}}
now take the square root of both sides
{{{x^(-2*(1/2)) = 4}}}
{{{x^(-1) = 4}}}
multiply both sides by {{{x}}}
{{{1 = 4x}}}
{{{x = 1/4}}} answer
check:
{{{x^(-2) = 16}}}
{{{(1/4)^(-2) = 16}}}
{{{1 / (1/4)^2 = 16}}}
multiply both sides by {{{(1/4)^2}}}
{{{1 = 16*(1/16)}}}
{{{1 = 1}}}
OK