12x/12 means 12 times x divided by 12 or 12 times x times 1/12 or we can move terms around using commutaive property 12 times 1/12 times x or 12/12 times x or 1 times x or x
So if you have X + 1 and you subtract 1 you would get just X, because addition and subtraction are opposites. Now if you have 12x and you divide by 12 what do you think you would get? That could be written like this [tex] \frac{12x}{12} [/tex]