What are 5 numbers that are not a solution

Enter the number of complex zeros for the polynomial function in the box. f(x) = x+ + 5x² +6

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.

How do you use the elimination method for this question? explain, because i really want to understand!