13 factored out is 13x - 39 add 39 to both sides it equals 13x=78 and 78 divided by 13 is 6 the anwser is x=6
Lets say you have an addition problem
3 + 7 = ?
To figure that you can just add in your head since its easy.
3 + 7 = 10
You can work backwords to check to see if your awnser is right.
When you work backwards you do the opposite of what you are doing, so if your adding the opposite would be subtracting, and if your multiplying than the opposite would be dividing.
So you could work it out like this:
(Regular⬇️)
3 + 7 = 10
(Backwards⬇️)
10 - 7 = 3
And if you get the same numbers that were in the original awnser than you are correct! Hope this helps!!!!
