Choose the definition for the function PLS HELP

Which equation and solution can be used to solve this problem? thirteen less than a number is sixteen. 13-n=16: add 13 to both sides. the answer is 29. n+13=16: subtract 13 from both sides. the answer is 3. n+16=13 subtract 13 from both sides. the answer is 3. n-13=16: add 13 to both sides. the answer is 29.

Which of the following is the missing term, a2, of the geometric sequence in which a1=2 and a3=200

Arrange these numbers from least to greatest 3/5 5/7 2/9