How many ways can Patricia choose 2 pizza toppings form a menu of 9 toppings if each topping can only be chosen once?

36

Step-by-step 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