You have to multiple and divide
We must find UNIQUE combinations because choosing a,b,c,d... is the same as d,c,b,a...etc. For this type of problem you use the "n choose k" formula...
n!/(k!(n-k)!), n=total number of choices available, k=number of choices made..
In this case:
20!/(10!(20-10)!)
20!/(10!*10!)
184756
Answer:
10
Step-by-step explanation:
Answer:
Below in bold.
Step-by-step explanation:
4x + y = 9
Let's put x = 0 then:
4(0) + y = 9
0 + y = 9
y = 9
So one. ordered pair that is a solution is (0, 9)