Answer:
36
Explanation:
There are 9 different toppings
Pick the first topping
Now there are 8 toppings
Pick the second topping
9*8
72 ways to pick the toppings
But order doesn't matter
pepperoni and hamburger is the same as hamburger and pepperoni, so we divide by 2
72/2 = 36
There are 36 different ways