Avariable whose value is less than zero is called

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.

Can someone show me step by step how to do this?

Which of the following is another way to express the difference between -5 and 8?