2^(2X) - 5 x 2^(X) + 6 = 0
Let $\displaystyle y = 2^x$.
Then this equation becomes
$\displaystyle y^2 - 5y + 6 = 0$
Can you factor this?
(By the way, I strongly discourage the use of "x" as a multiplication symbol at this point in your education. It looks too much like the variable x. You can use the * for multiplication if you need a symbol.)
-Dan