Please help! this is due my today and i don't understand it

What is the rescursive formula for this geometric sequence? 7, -14, 28, -56

The graph shows the distance y, in inches, a pendulum moves to the right (positive displacement) and to the left (negative displacement), for a given number of seconds x. how many seconds are required for the pendulum to move from its resting position and return? enter your answer in the box.

Add the fractions and simplify 1/2+ 1/3