Which represents a quadratic function?

f(x) = −8x^3 − 16x^2 − 4x

f (x) = 3/4 x ^2 + 2x − 5

f(x) = 4/x^2 - 2/x + 1

f(x) = 0x^2 − 9x + 7

A quadratic equation is of the format:

ax² + bx + c = 0,  where a ≠ 0.

The first option is not quadratic, it is a cubic, it has highest power of 3.

The second option f (x) = 3/4 x ^2 + 2x − 5, is quadratic, that is the answer.

The third f(x) = 4/x^2 - 2/x + 1, doesn't qualify because of the 2/x.

The last f(x) = 0x^2 − 9x + 7 , doesn't qualify because of the a = 0, and the rule is that a ≠ 0.

Therefore  f (x) = 3/4 x ^2 + 2x − 5 represents a quadratic function.

I hope this helps.

Hello,

a quadratic function has y=ax²+bx+c with a!=0 for equation.
Thus the only answer is f(x)=3/4 x²+2x-5