Question

Please help me on 5 I don’t know what I did wrong on the last two

Answer 1

`\begin{gathered} a_n=18-3(n-1) \\ a_(100)=-279 \end{gathered}`

Explanation:

We have the following sequence:

`18,15,12,9\ldots`

Therefore, the sequence is:

`a_n=18-3(n-1)`

Now, when n is 100:

`\begin{gathered} a_(100)=18-3(100-1) \\ a_(100)=18-297 \\ a_(100)=-279 \end{gathered}`