Which set of coordinates represents a function

The third option is correct. It is because all the values of x maps to a single unique value of y.

A function is a mathematical relation which assigns only one value to each input it takes.

It contradicts the definition of function as:

(1,1), (1,2) denotes that input 1 maps to output 1 and output 2 both. Thus it is not a function.

It doesn't satisfies the definition of function as:

(3,3) (3, -3) denotes that 3 maps to both 3 and -3 as output. Thus it is also not a function.

It is a function since it outputs only single value to each input it takes, viz:

(0,5), (1, 10), (2, 15) ,(3, 20), (4, 25)

It doesn't satisfies the definition of function as:

(-2,4) and (-2,-4) tells that -2 outputs two values 4 and -4. Thus it is not a function.

Thus, only option 3 given is a valid function.

Learn more about functions here:

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the third set represent a function

For the points to represent a function then for each value of x there can only be one corresponding value of y

sets 1, 2 and 4 do not obey this and have more than one value of y for a given x

set 1

1 → 1, 2, 3, 4, 5

set 2

3 → 3, - 3 and 5 → 5, - 5

set 4

- 1 → - 1, 1 and - 2 → 4, - 4

john earns $14.00 for two hours of work.