Question

Simplify 9c4combinations

Answer 1

Step-by-step explanation:

Given;

We are given the following information;

`_9C_4`

Required;

We are required to simplify the expression;

"Number of combinations of 9 things taken 4 at a time."

Step-by-step solution;

The formula for solving combinations is;

`_nC_r=(n!)/((n-r)!* r!)`

We can now substitute the given values and solve;

`_9C_4=(9!)/((9-4)!*4!)`
`_=(9*8*7*...1)/((5*4*3*...1)*4*3*2*1)`
`=(362880)/(120*24)`
`=(362880)/(2880)`
`=126`

Therefore;

ANSWER:

`_9C_4=126`