Answer:
You can use the equation " 17 +b = 28 " to check is she's right because 17 +b has to be 28 baseballs.
Step-by-step explanation:
Sorry for that answer but what I meant was that 17 + b (How many baseballs can be added) must be 28. Now you can subtract both sides by 17 to isolate b by itself. When you do that you get b= 11. So you can add 11 more baseballs instead of 9, therefore she is wrong.
You can check this by putting 11 in for b in the equation. 17+11=28. This is correct.
Hopefully this helped you.