Solve the equation 3^(x+1)+3^(x+2)=108

We'll re-write the
equation:

3*3^x +
9*3^x=108

We'll factorize by
3^x:

3^x*(3 + 9) = 108

12*3^x
= 108

We'll divide by 12:

3^x
= 9

We'll create matching bases writting 9 as a power of
3:

3^x = 3^2

Since the bases
are matching now, we can apply one to one rule:

x =
2

The solution of the given equation is x =
2.