Answers
A function is a relationship between a set of inputs where each input has exactly one output. So any set will not have any x value repeated in the set.
6. Set #2 is a function, no x value repeats in the set
7. Set #4 is a function, no x value repeats in the set
8. Answer is #4, there are multiple y values for every x value. *note: look at the circle. If you had x=2, you would have a y value in quadrant 1 AND in quadrant 4, so you would have two points with the same x value. This can be represented with the vertical line test. Draw a vertical line, if the line hits two points on the line, it is NOT a function. See attachment.
9. Points (0, 2) and ( 0, -1) repeat the x value of (0) so your answer would be #4 to remove ( 0, -1) to make this set a function
10. Answer #4 = 4 would replace “a” and keep this set a function because 4 is not repeated as an x value in the set.