I got you hun!
27= 3x is the equation you will need
27 is the total the coach needs making it the total. Since each pack comes with 3 you will mutiply the amount of pack, or x, by 3.
X=9
we know this because if you divide 3 by 27 to get it on the other side we get 9. This means the coach needs to buy 9 packs of baseballs for the team.
27=3(9)
Hope this helps!