Answer:
subtract
Step-by-step explanation:
(2x² + 7x + 10) - (x² + 2x - 9) =
2x² + 7x + 10 - x² - 2x + 9 =
x² + 5x + 19
Answer:
455 or 680, depending
Step-by-step explanation:
If we assume the three choices are different, then there are ...
15C3 = 15·14·13/(3·2·1) = 35·13 = 455
ways to make the pizza.
___
If two or three of the topping choices can be the same, then there are an additional ...
2(15C2) +15C1 = 2·105 +15 = 225
ways to make the pizza, for a total of ...
455 + 225 = 680
different types of pizza.
__
There is a factor of 2 attached to the number of choices of 2 toppings, because you can have double anchovies and tomato, or double tomato and anchovies, for example, when your choice of two toppings is anchovies and tomato.
_____
nCk = n!/(k!(n-k)!)
