Which set of ordered pairs is not a function?A. (4, –2), (–2, 2), (2, –2), (4, 2)
B. (–4, 2), (–2, 2), (2, 2), (4, 2)
C. (–4, 2), (–2, –2), (2, 2), (4, 2)
D. (–4, –2), (–2, –2), (2, 2), (4, 2)
Look for ordered pairs (x,y) with identical x-values. If the corresponding y-values are different, the ordered pairs do not form a function. This is the equivalent of the vertical line test (i.e. no vertical line cuts two points).
However, in case where both x and y values are identical, that means the points are just duplicates, and does not violate the vertical line test. Look for others, if any.
In (A), what can you say about the pair of ordered pairs indicated in bold?
A. (4, –2), (–2, 2), (2, –2), (4, 2)
In A there are two values of y , -2 and + 2, for the same value of x, 4
That is a no no
if a value of x maps to two different y's, it is not a function.
So, look for a line with a repeated 1st element.
I don't understand
If y=f(x) maps a value of x to a value of y, then look at the first line. It says
f(4) = -2
f(4) = 2
it cannot be both. So, (A) is not a function.
Three math teachers explained this to you. I suggest that you study your text or hire a math tutor who can help you in person.
To determine whether a set of ordered pairs represents a function, we need to check if each input (x-value) is associated with only one output (y-value).
Let's analyze each set of ordered pairs:
A. (4, -2), (-2, 2), (2, -2), (4, 2)
In this set, the input value 4 is associated with two different output values, -2 and 2. Therefore, set A is not a function.
B. (-4, 2), (-2, 2), (2, 2), (4, 2)
In this set, each input value is associated with the same output value, 2. Therefore, set B is a function.
C. (-4, 2), (-2, -2), (2, 2), (4, 2)
In this set, the input value -2 is associated with two different output values, -2 and 2. Therefore, set C is not a function.
D. (-4, -2), (-2, -2), (2, 2), (4, 2)
In this set, each input value is associated with a unique output value. Therefore, set D is a function.
Therefore, the set that is not a function is set A: (4, -2), (-2, 2), (2, -2), (4, 2).