Answer
See below.
Work Step by Step
The nth term of an arithmetic sequence can be obtained by the following formula: $a_n=a_1+(n-1)d$, where $a_1$ is the first term and $d$ is the common difference.
Hence here: $d=7-3=4,n=9,a_1=3,a_{9}=3+(9-1)4=3+32=35$