# Math Help - Simplifying an algebraic equation

1. ## Simplifying an algebraic equation

Hi, can someone please explain why

simplifies to

and not

I'm fully confused on it

2. How would you simplify 2(x - 1) + x?

Do the same thing here.

3. I think I know where you made the mistake...

Ok, trick question: What is $3(3^{n-1})$? If you answered $9^{n-1}$, you made a mistake.

Remember the rules on multiplying things with exponents with the same base?

$x^2*x$ is the same as $x^2*x^1$, of course. And since you're multiplying, you need to add the exponents. So $x^2*x = x^3$.

So, in fact, $3(3^{n-1}) = 3^{n-1+1} = 3^n$. Which makes your answer $3^n - 2$ and definitely not $9^{n-1} - 2$.

Hope that clears it up! Easy mistake to make.

4. Thanks guys, I understand now.