SOLUTION: I add 3 to the number, multiply the result by 2, I get the same as I add 13 to it. If possible can I get Brysca to answer this.

I don't want to do your work for you, so Ill do one exactly like yours so you
can do your own problem and use the one I do as a guide.  Yours is exactly
like it.

I start with 

N

So I write + 6 after the N, now I have this:

 N + 6

Now before I can multiply that, since there are two terms, I must
put parentheses around it, like this (N + 6), so that when I multiply
it by 2, both terms will be multiplied by 2 and not just the N only.
So now I have

2(N + 6)

"I get the same as" means to put an equal sign after it because when
things are the same they are equal:

2(N + 6) =

Adding 19 to N was just like adding 6 to it.  We get N + 19. So you
write N + 19 after the equal sign:

2(N + 6) = N + 19

Now that's an equation.  To solve it

Distribute to remove the parentheses:

2N + 12 = N + 19

Then I get rid of the + 12 on the left by adding -12 to both sides.

2N + 12 = N + 19
    -12      -12
----------------
2N      = N +  7

Then I get rid of the N on the right side by adding -N to both sides:

     2N = N + 7
     -N  -N
     ----------
      N =     7

The answer is 7.

Edwin