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Big Ideas Math Geometry, 2014

BI

Big Ideas Math Geometry, 2014 View details

5. Permutations and Combinations

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Exercise 25 Page 704

Recall the formula for a combination, _n C_r = n!/(n-r)! r!.

5

Practice makes perfect

To evaluate the given combination, we will use the corresponding formula. _n C_r = n!/(n-r)! r! We are given that n=5 and r=1. Let's substitute these values into the formula.

_n C_r = n!/(n-r)! r!

n= 5, r= 1

_5 C_1 = 5!/( 5- 1)! 1!

Subtract term

_5 C_1 = 5!/4! 1!

Write as a product

_5 C_1 = 5* 4!/4! 1!

a/b=.a /4!./.b /4!.

_5 C_1 = 5/1!

1!=1

_5 C_1 = 5/1

a/1=a

_5 C_1 = 5

Subchapter links

Communicate Your Answer p.699

Monitoring Progress p.700-703

Exercises p.704-706