# Given the nth term for each arithmetic sequence, how to find the indicated term here? (1) a_n=6n+1; a_12 (2) a_n=3n-5; a_20

Jun 27, 2018

1) 73
2) 55

#### Explanation:

1) ${a}_{\textcolor{red}{n}} = 6 \textcolor{red}{n} + 1$

For ${a}_{12}$ where ever there is an $\textcolor{red}{n}$ write 12 giving:

${a}_{12} = 6 \left(12\right) + 1 \textcolor{w h i t e}{\text{d") ->color(white)("d}} {a}_{12} = \left[6 \times 12\right] + 1 = 73$

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2) ${a}_{\textcolor{red}{n}} = 3 \textcolor{red}{n} - 5$

For ${a}_{\textcolor{red}{20}}$where ever there is an $\textcolor{red}{n}$ write 20 giving:

${a}_{\textcolor{red}{20}} = 3 \left(\textcolor{red}{20}\right) - 5 \textcolor{w h i t e}{\text{d")->color(white)("d}} {a}_{20} = \left[3 \times 20\right] - 5 = 55$