Question 898996
{{{9^(x+1)-3^(x+3)-3^x+3=0}}}
{{{(3^2)^(x+1)-3^(x+3)-3^x+3=0}}}
{{{3^(2*(x+1))-3^(x+3)-3^x+3=0}}}
{{{3^(2x+2)-3^(x+3)-3^x+3=0}}}
{{{9*3^(2x)-27*3^(x)-3^x+3=0}}}
{{{9*3^(2x)-28*3^(x)+3=0}}}
Substitute {{{u=3^x}}}

{{{9u^2-28u+3=0}}}
{{{(u-3)(9u-1)=0}}}
Two solutions:
{{{u-3=0}}}
{{{u=3}}}
{{{3^x=3}}}
{{{x=1}}}
and
{{{9u-1=0}}}
{{{9u=1}}}
{{{u=1/9}}}
{{{3^x=1/9}}}
{{{x=-2}}}