Question

Which represents a quadratic function? f(x) = −8x3 − 16x2 − 4x f (x) = x 2 + 2x − 5 f(x) = + 1 f(x) = 0x2 − 9x + 7

Answer 1

The answer is f(x)=x^2+2x-5
A quadratic formula must have at least one square (x^2) and cannot have higher exponents.
The reason 0x^2 doesn't count is because that will always equal zero no matter the value of x, which makes that term a constant.

Answer 2

Answer: The correct answer is
`f(x)=x^2+2x-5`

Explanation:

A Quadratic equation is defined as the equation in which the highest power of the variable is 2. The general form of this equation represents:

`ax^2+bx+c=0`

where,
`a\\eq 0`

From the given options:

1.
`f(x)=-8x^3-16x^2-4x`: Here, the highest power of the variable is 3. Therefore, it is not a quadratic equation.

2.
`f(x)=x^2+2x-5`: Here, the highest power of the variable is 2. Therefore, it is a quadratic equation.

3.
`f(x)=+1`: Here, the highest power of the variable is 0. Therefore, it is not a quadratic equation.

4.
`f(x)=0x^2-9x+7`: Here, the highest power of the variable is 1. Therefore, it is not a quadratic equation.

Hence, the correct answer is
`f(x)=x^2+2x-5`