Question 869378
I corrected what I think is a missing parentheses in the first term.
{{{2^(2+2t) + 3(2^t) - 1 = 0}}}
{{{4*2^(2t)+3*2^t-1=0}}}
Substitute,
{{{u=2^t}}}
{{{u^2=2^(2t)}}}
{{{4u^2+3u-1=0}}}
{{{(u+1)(4u-1)=0}}}
Only the positive solution makes sense for this problem.
{{{4u-1=0}}}
{{{4u=1}}}
{{{u=1/4}}}
{{{2^t=1/4}}}
{{{t=-2}}}