Question

21g = 84 A. g = 3 B. g = 4 C. g = 5

Answer 1

21g=84
g=84/21
g=4

The answer is B

Answer 2

21g = 84
You divide each side by 21 so you can get "g" alone on a side, and another number which represents the value of "g" on the other side.
(21g)/21 = 84/21
g = 4.

So the correct answer is B: g = 4.

You can re-check your answer (very important):
21g = 21 * 4 = 84

Hope this Helps! :)