Which of the following statements best describes the relationship of a relation and a function

A statementent of the relationship and a function is that the numbers from the x-axis cannot be double number with another number heres an example.

For Example:
1 6
7 4
5 2

Ok for example the number seven can only be with only one of the numbers from the right side but the number from the right side can be with more than one number get it now?

I hope this helps you for your math class.

For this case, what we are going to do is verify in which points the function is equal to zero.
 We have the points are:
 x = (-b +/- root (b ^ 2 -4 * a * c)) / (2 * a)
 We substitute the values in the equations shown and verify that the equality is met.
 For y = 2x2 + 8x - 5
 x1 = -2-root (13/2)
 x2 = root (13/2) - 2
 These roots coincide with the cut points of the graph on the x axis.
 
 The equation is:
 y = 2x2 + 8x - 5
 option 4