So, say order mattered. If we had x toppings and we only wanted groups of two different toppings, we would have x toppings for the first option, and x-1 toppings for the second option since we've already used a topping. Using the multiplication rule that would give us x(x-1) different groups, if order mattered, which is written as:

So, in this specific problem order does not matter. We see that we've overcounted because for every pair of toppings we have, they can be reordered 2!=2 ways. So that means we must divide by two to get:

Which is written as:

Just send it duude im down 34-895
Answer with explanation:
If Submarine position is 600 feet below sea level, it can be represented in terms of integers as = - 600
Now , it descends 218 feet ,from where it is presently Located.
Descend in terms of integers can be represented as = - 218 feet
Submarine New position or Elevation = - 600 feet + (-218 feet)
= -818 feet
Option A : -818 feet
I really wish i could help but i forgot how to do this