Which equation best represents this situation? the number 39 is equal to 13 subtracted from an unknown number. a. 39 = r ÷ 13 b. 39 = 13 + r c. 39 = r – 13 d. 39 = 13r

C! 39 is being subtracted. it's the only one where it's being subtracted. r is the unknown. 13 is being subtracted from r.

39 = r - 13

It would be C :)

WHY? 

Because r is our unknown number, and if 13 is subtracted from it, then you know that it looks like : r - 13 :)

Thus, making our answer C) because it is the only one that has 13 being subtracted.

~Hope I helped!~

Ican't do any of the other stuff, but i can get you started. the answer, i believe, is $2.50.