Which equation can be used to find the length of Line segment A C?

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)

Which of the following will form the composite function?

Write a linear funtion f with the values f(2)=-1, and f(5)=4