Which function is a quadratic function?
f(x) = 2x2
g(x) = 5x3
k(x) = –x
b(x) = –9x4

  f(x)

Step-by-step explanation:

A quadratic function is a degree 2 function. That is, it is a polynomial function with the highest power of the variable being 2.

f(x) is a quadratic function

Other choices:

  g(x) is cubic (3rd degree)

  k(x) is linear (1st degree)

  b(x) is quartic (4th degree)

f(x) = x^3 -2x^2 -3x

x( x^2 -2x-3)

x( x^2 +x -3x -3)

x( x(x+1) -3(x+1))

x( x-3)( x+1)

so zeroes are 0, 3,-1

its (2) option