HELP. please?

Answers:

Functions

Not functions

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Explanation:

A function is possible if and only if any given x input leads to exactly one y output.

For something like x^2+y^2 = 81, we can see that x = 0 leads to either y = 9 or y = -9. So this would not be a function. We would need x to pair with only y value to have it be a function.

We have the same thing going on with y^2 = -5x-12 as well.

For anything of the form x = k, where k is any real number, this is also not a function. We have one single input only and it leads to infinitely many outputs. So in a sense, this is even worse compared to the other examples.

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In summary, we have these three non-functions:

Everything else is a function. You can use the vertical line test as a visual way to check.

explanation:

step-by-step explanation: