
You get this by switching the f(x) and the x and then solving for the new f(x)
It equals because when you multiply it all up
3(x + 2)
3(x) + 3(2)
3x + 6

<h3>Hope This Helps You</h3>
We know that
The formula for combinations is
C=n!/[(n-r)!*r!]
where
n is the total number of objects you choose from
r is the number that you choose to arrange
in this problem
n=15 students
r=4 students
C=15!/[(15-4)!*4!]-----> C=15!/[11!*4!]---> (15*14*13*12*11!)/(11!*4*3*2*1)
C=(15*14*13*12)/(24)----->C=1365
the answer is
1365