Question 151581
{{{y=2^(5x+1)}}}
{{{y=4^(-x)}}}

{{{2^(5X+1) = 4^(-x)}}}
{{{2^(5x+1) = (2^2)^(-x)}}}
{{{2^(5x+1) = 2^(-2x)}}}
{{{(5x+1) = -2x}}}
{{{7x = -1}}}
{{{x = -1/7}}}

Plug in and verify