Im in 9th Grade this is Algebra 1 and I fell like I knew this before but I forgot completely it's the last piece of H.W I have left for today any help?

Do you mean this:

(3x)9 = 12?

Combine the integers, then rearange to get x by itself::

27x = 12
x= 12/27

Maybe this:

3x + 9 = 12

or

3x - 9 = 12

In any case, you should add/subtract/divide/multiply both sides by something in order to 'remove' numbers so that you are left with x alone.

In

3x + 9 = 12

Subtract 9 from both sides:

3x + 9 - 9 = 12 - 9

3x = 3

Then divide both sides by 3:

\frac{3x}{3} = \frac{3}{3}

x = 1