How do I solve 12 × (r +13) / 12?

Question

I'm trying to explain how to work through identifying a variable. 

Answer 1

12 × (r +13) / 12 = 

 

r + 13,  because both the numerator and the denominator have 12 x something.  So, you can see that 12/12 = 1.

 

If you had put this expression = to 0, which you did not, then   r + 13 = 0, r = -13