Answer:
3 platters
Explanation:
You need to find a factor of both 9 and 12. The only common factors are 1 and 3. Then, you pick the largest, which is 3 in this instance. Then, you can figure out how many pieces of each would be on a platter. 9/3=3, so there will be 3 slices of cheese on a platter, and 12/3=4, so there will be 4 veggie pizza slices on each platter.