Question

PLEASE! I NEED HELP. ITS VERY EMERGENCY

Answer 1

Here it is:

The first set has (0,1) and (0,5), which assigns to the *same* x, more than one value of *y*. That's not a function. It's a curve. Think about a circle, or instance. It's NOT a function, but it's a curve.

The second one has for each *x* a single *y*

BTW, there's no problem if for *different* x there is the same *y*:

y = 5,

all x, have the same y, equal to 5. That's a function, or y = x^2, etc

Answer 2

The definition of a function is that for every unique input, independent variable, there is only one unique output, dependent variable.  Otherwise is fails what is called the "vertical line test" which just means that there can only be one specific output value for any one specific input value.