What is f(-3) i need help plzzz

For the equations below which statement is true ?

How do i start to solve? would appreciate a walk-thru! a bird sitting 16ft above the ground in an apple tree dislodges an apple. after how many seconds does the apple land on the ground? (assuming that no branches will interfere with it's fall)

What is the 17th term in the arithmetic sequence in which a6 is 101 and a9 is 83