Question

Is f(x)=x^2-1 a quadratic function?

Answer 1

`f(x) = x^2-1` is a quadratic function

Explanation:

Any expression that can be written in the form:
`color(white)("XXXX")` `f(x) = ax^2+bx+c`
is a quadratic function.

`f(x)=x^2-1`
is equivalent to `f(x) = 1 * x^2 +0 * x + (-1)`

The fact that the coefficient of `x` is `0` does not prevent this from being a quadratic function.

Answer 2

Any function containing the highest degree as `2` is quadratic. So:

`Ax^2 pm Bx pm C` is quadratic
where `A != 0` and `B` and `C` are anything real

`Ax^3 pm Bx^2 pm Cx pm D` is not (it's cubic)
where `A != 0` and `B`, `C`, and `D` are anything real