Which represents a quadratic function

The only quadratic function is the second one listed:

Step-by-step explanation:

A quadratic function must contain have a non-zero leading term with the variable to the power "2". Therefore, the first function listed is not a quadratic function,but a cubic function (leading term contains )

The second function listed is a quadratic function, whose leading term is quadratic and of the form

The third function is not a quadratic function, since it doesn't have a leading term of power "2".Notice that the term   so the power of x is not 2 but "-2"

The fourth function has a zero coefficient for the term in , so that term does not really appear in the expression (is a zero)

So the only quadratic function is the second one listed:

i dont get it. where are the "descriptions"?

the answer is 11.2 (i know i’m late)