For the sequence an = 4n + 5 how do you find the first five terms?

Aug 31, 2015

The first five terms are
color(blue)(9,13,17,21,25

Explanation:

${a}_{n} = 4 n + 5$

We can find terms $1$ to $5$ by substituting $n$ respectively in the expression.

${a}_{n} = 4 n + 5$

So,
${a}_{\textcolor{b l u e}{1}} = 4 \cdot \textcolor{b l u e}{\left(1\right)} + 5 = 9$

${a}_{\textcolor{b l u e}{2}} = 4 \cdot \textcolor{b l u e}{\left(2\right)} + 5 = 13$

${a}_{\textcolor{b l u e}{3}} = 4 \cdot \textcolor{b l u e}{\left(3\right)} + 5 = 17$

${a}_{\textcolor{b l u e}{4}} = 4 \cdot \textcolor{b l u e}{\left(4\right)} + 5 = 21$

${a}_{\textcolor{b l u e}{4}} = 4 \cdot \textcolor{b l u e}{\left(5\right)} + 5 = 25$