Question

Which of the following is a quadratic function​

Answer 1

A quadratic a function has a form of,

$f(x)=ax^2+bx+c,a\neq0$

The first function has a term $x^3$ which doesn't fit the profile of a quadratic function. The highest exponent on x inside a quadratic function can be 2, but here we have 3 so this is not a quadratic function, but rather a cubic function.

The second function fits the form of a quadratic function perfectly.

The third function is a bit tricky. While technically the third function could be considered quadratic if the leading term would be something like $0x^2$ and we did't even see it written out because multiplying with 0. But when we specified the form of a quadratic function, we strictly said that the number before $x^2$ aka $a$ cannot equal to zero. So the last function is not a quadratic function but rather a linear function.

Hope this helps :)

Answer 2

Step-by-step explanation:

f(x) = 4x² + x - 3

$f(x) = 4x {}^{2} + 3 - 2$

r3t40 is correct