Please show me step by step how to do this

Answer:
The next three terms of the sequence are 17, 21 and 25.
The 300th term of the sequence is 1197.
Step-by-step explanation:
The statement describes an arithmetic progression, which is defined by following formula:
[tex]p(n) = p_{1}+r\cdot (n-1)[/tex] (1)
Where:
[tex]p_{1}[/tex] - First element of the sequence.
[tex]r[/tex] - Progression rate.
[tex]n[/tex] - Index of the n-th element of the sequence.
[tex]p(n)[/tex] - n-th element of the series.
If we know that [tex]p_{1} = 1[/tex], [tex]n = 2[/tex] and [tex]p(n) = 5[/tex], then the progression rate is:
[tex]r = \frac{p(n)-p_{1}}{n-1}[/tex]
[tex]r = 4[/tex]
The set of elements of the series are described by [tex]p(n) = 1 + 4\cdot (n-1)[/tex].
Lastly, if we know that [tex]n = 300[/tex], then the 300th term of the sequence is:
[tex]p(n) = 1 + 4\cdot (n-1)[/tex]
[tex]p(n) = 1197[/tex]
And the next three terms of the sequence are:
n = 5
[tex]p(n) = 1 + 4\cdot (n-1)[/tex]
[tex]p(n) = 17[/tex]
n = 6
[tex]p(n) = 1 + 4\cdot (n-1)[/tex]
[tex]p(n) = 21[/tex]
n = 7
[tex]p(n) = 1 + 4\cdot (n-1)[/tex]
[tex]p(n) = 25[/tex]
The next three terms of the sequence are 17, 21 and 25.
The 300th term of the sequence is 1197.