Question

Which function is a quadratic function?u(x) = –x + 3x2 – 8v(x) = 2x2 + 8x3 + 9xy(x) = x2 + 3x5 + 4z(x) = 7x2 + 2x3 – 3

Answer 1

The quadratic function:

`f(x)=ax^2+bx+c,\ a\\eq0`

Answer:
`u(x)=-x+3x^2-8=3x^2-x-8`

Answer 2

`u(x) = -x + 3x^2 - 8`

Explanation:

Quadratic function is in the form of
`y=ax^2+bx+c` with largest exponent as 2

`u(x) = -x + 3x^2 - 8` can be written as
`u(x) =3x^2-x - 8`

is in the form of y=ax^2 + bx +c with largest exponent 2. so it is quadratic function.

`v(x) = 2x^2 + 8x^3 + 9x`. It is not quadratic because it has largest exponent 3.

`y(x) = x^2 + 3x^5 + 4`. It is not quadratic because it has largest exponent 5.

`z(x) = 7x^2 + 2x^3 - 3` It is not quadratic because it has largest exponent 3.