Hello,

I 'd appreciate help with the below questions :)

1.

2.

3.

Guest Mar 19, 2019

edited by
Guest
Mar 19, 2019

#1**+1 **

1. The common difference is 33......the first term is 20

So.....the formula is for the number sold in the nth week is

20 + 33 ( n - 1) =

20 + 33n - 33

33n - 13

2. a_{n} = -2n + 7

First term is -2(1) + 7 = 5

Second term is -2(2) + 7 = 3

So....the common difference is - 2

So....the recursive rule is a_{n} = a_{n-1} - 2

So.....

a_{1} = 5 a_{n} = a_{n-1} - 2

3. 2, 9, 16, 23 , 30

The common difference is 7

The first term is 2

So....the explicit formula for the nth term is

a_{n} = 2 + 7 ( n - 1) = 2 + 7n - 7 = -5 + 7n

CPhill Mar 19, 2019

#2**0 **

Thanks, Cphill!

I really struggle with these types of questions, so if you could help with these questions also that would be greatly appreciated!

1st one:

2nd one:

Guest Mar 19, 2019

#3**+1 **

First one

-2.7, -8.3, -13.9 , -19.5, -25.1

The common difference is -8.3 - (-2.7) = -5.6

The first term is -2.7

So....the recursive rule is

a_{n} = a_{n-1} - 5.6 where a_{1} = -2.7

Second one :

12.5, 11, 9.5.....

The common difference is 11 - 12.5 = -1.5

The first term is 12.5

So....the explicit rule is

a_{n} = a_{1} - 1.5(n - 1) = 12.5 - 1.5n + 1.5 = 14 -1.5n

CPhill
Mar 19, 2019