Question 299939
I'm not sure if you meant 
{{{f(x)=-2(3^x-1)+1}}} in red or
{{{f(x)=-2(3^(x-1))+1}}} in green. 
{{{ graph( 300, 300, -5, 5, -10, 10, -2(3^x-1)+1, -2(3^(x-1))-1 )}}} 
.
.
.
Stages?