Question

Which set of ordered pairs does not represent a function?

Answer 1

B.
Its because if you look at the x coordinates (which would be the first number in an ordered pair) there are two -7s.

remember that each input (the x coordinate), must have exactly one output (the y coordinate)

hope you understand

Answer 2

Answer: Choice B

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Step-by-step explanation:

There's a lot of items here to get lost in. We'll focus on choice B and the first two points in this set. Note how those two points have x = -7 repeated. Whenever x repeats itself, this means we do not have a function. The input x = -7 leads to multiple outputs (y = 1 and y = -3 simultaneously). A function is only possible when any input leads to exactly one and only one output. Visually, you can use the vertical line test to see how graph B fails to be a function.

In choices A, C and D, the x values are not repeated for any given answer choice. For instance, choice A has x = 9, x = -4, x = 6 and x = 8 none of which are repeats. So choice A is a function. Choices C and D are similar stories. These graphs pass the vertical line test. So that's why we can rule these answer choices out.