Answer:
Students(s) = 192.
Explanation:
Eq:
3s + 9 = 585 (each group of 3 wrote 9 each, so for every group + 9. S = students and 585 is altogether.)
Isolate the 3s by doing the inverse (-) of addition and we do that by subtracting 9 from itself and 585.
Eq: 3s = 576
Lastly, isolate the s by dividing 3 (inverse of *)
Eq:
576
___
3
( s = 192 )