Let $a_1,a_2,a_3,\dots ,a_n,\dots$ be an arithmetic sequence. Find $a_{10}$ and $S_{20}$
$$a_1=17,d=3$$
$$a_{10}=$$
(Simplify your answer.)

Step 1 ：Given an arithmetic sequence where the first term $a_1=17$ and the common difference $d=3$.

Step 2 ：We are asked to find the 10th term of the sequence, $a_{10}$.

Step 3 ：In an arithmetic sequence, the nth term can be found using the formula $a_n=a_1+(n-1)d$, where $a_1$ is the first term, $d$ is the common difference, and $n$ is the term number.

Step 4 ：Substitute $a_1=17$, $d=3$, and $n=10$ into the formula to find $a_{10}$.

Step 5 ：$a_{10}=17+(10-1)\times 3=44$.

Step 6 ：We are also asked to find the sum of the first 20 terms of the sequence, $S_{20}$.

Step 7 ：The sum of the first n terms of an arithmetic sequence can be found using the formula $S_n=\frac{n}{2}(a_1+a_n)$, where $a_1$ is the first term, $a_n$ is the nth term, and $n$ is the number of terms.

Step 8 ：Substitute $a_1=17$, $a_n=44$, and $n=20$ into the formula to find $S_{20}$.

Step 9 ：$S_{20}=\frac{20}{2}(17+44)=610$.

Step 10 ：Final Answer: The 10th term of the arithmetic sequence is $\boxed{{\displaystyle 44}}$ and the sum of the first 20 terms of the sequence is $\boxed{{\displaystyle 610}}$.