PATTERNS, FUR1 2013 VCAA 1 MC The first three terms of an arithmetic sequence are 3, 5 and 7. The ninth term of this sequence is A. `9` B. `17` C. `19` D. `21` E. `768` Show Answers Only `C` Show Worked Solution `text(AP is 3, 5, 7 …)` `a=3,\ \ \ d=5-3=2` `T_n` `=a+(n-1)d` `T_9` `=3+(9-1)2` `=19` `=> C`