Exercise 14 Page 287

To find certain terms in a sequence described by an explicit formula, substitute the number of the desired term into the formula to get the term's value. For the given explicit formula, A(n)=- 9+(n-1)(3),we can find the second, fourth, and eleventh terms of the sequence by substituting 2, 4, and 11 into the formula for n.

A(n)=- 9+(n-1)(3)

Substitute

n= 2

A( 2)=- 9+( 2-1)(3)

SubTerm

Subtract term

A(2)=- 9+(1) (3)

IdPropMult

Identity Property of Multiplication

A(2)=- 9+3

SubTerm

Subtract term

A(2)=- 6

Now, let's do the same thing for the fourth and eleventh terms.

n^(th) term	- 9+(n-1)(3)	A(n)
2	- 9+( 2-1)(3)	- 6
4	- 9+( 4-1)(3)	0
11	- 9+( 11-1)(3)	21

The second, fourth, and eleventh terms are - 6, 0, and 21.