Ernise evaluated the expression 10(3 + 5) like this:
step 1: 10.3 + 10.5
step 2: 30 + 50
step 3: 80
which mathematical property was she using?

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.