Exponential Equation In Quadratic Form

[chillfactor]

Homework Statement

The problem is 3^2x+3^(x+1)-4=0

I know I had to solve it by substitution

Homework Equations

The Attempt at a Solution

I had u = 3^x
I put it in:
(u )(u ), but I was not sure how to get the middle term 3^(x+1)

 

[llello]

You could write 3^(x+1) = 3^x * 3^1

 

[Mentallic]

chillfactor, that's a bad way to do it. Take this slowly, step by step.
First make the substitution, then once it is in the general quadratic form $$au^2+bu+c=0$$ THEN solve for u either by factorizing or using the quadratic formula. After doing that, substitute back in and solve for x.