Question

Why do i have to subtract 3 from both sides of the following equation instead dividing by 9 first.

Answer 1

Because the 3 doesn't have a "letter" behind it. You would subtract the 3 first and all you would have left on the left side of the expression will be 9x. then on the other side of the expression you would subtract 3 from 27. So, 27 minus 3. After you get the answer from 27 minus 3, you will then divide that answer by 9. Then you have the answer or what "x" equals after you divide by 9.

Answer 2

You are trying to find x, and you need to isolate it as much as possible

Remember PEMDAS

you are pretty much doing the opposite of it, or SADMEP, to find x

hope this helps

9x + 3 = 27
9x + 3 (-3) = 27 (-3)
9x = 24
9x/9 = 24/9

x = 8/3