If 6 of the 13 books are new, then 7 of them are used. The ratio of new (6) to used (7) is
6:7 or 6/7
Ratio of all books (13) to used books (7) is
13:7 or 13/7
Recall the binomial theorem.

1. The binomial expansion of
is

Observe that


When we multiply these by
,
•
and
combine to make 
•
and
combine to make 
and the sum of these terms is

2. The binomial expansion is

We get the
term when
:

Answer:
64
Step-by-step explanation:
Answer:
b = 5
Step-by-step explanation:
89b = 411 + 34 (445)
89b = 445
b = 5
Answer:
Step-by-step explanation:
Exterior angle = 360/n
= 360/13
= 27.7°