Question

Which function is a quadratic function?

Answer 1

it's the first oneeeeeeeeeeeeeee

Answer 2

u(x) is the only quadratic function.

Explanation:

We are given four algebraic functions in x and we have to find which one is a quadratic function.

Let us arrange those polynomials in descending powers of x.

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

The highest degree is 2. Hence this is quadratic function.

ii)
`v(x) = 8x^3+2x^2+9x`

The highest degree is 3 and hence this is cubic

iii)
`y(x) = 3x^5+x^2+4`

The highest degree is 5 and hence this cannot be quadratic

iv)
`z(x) = 2x^3+7x^2-3`

The highest degree is 3 and hence this is cubic

Hence u(x) is the only quadratic function.