Solution for Section 4.1 Question 7
7. a)
10!
=
10 · 9 ·
8!
=
45
8! 2!
8!
· 2 · 1
b)
(n + 2)!
=
(n + 2) (n + 1)
n!
=
(n + 2) (n + 1)
n!
n!
Back to Section 4.1