Question 434777
I presume you really meant:
{{{ 9^(x-5) = 81^(x-7)}}}
{{{ 9^(x-5) = (9^2)^(x-7)}}}
{{{ 9^(x-5) = 9^(2(x-7))}}}
{{{ 9^(x-5) = 9^(2x-14)}}}
{{{ x-5 = 2x-14 }}}
{{{ -5 = x-14 }}}
{{{ 9 = x }}}