Question

The degree of the polynomial function f(x) is 4.

The roots of the equation f(x)=0 are −2, −1, 1 and 3.

Which graph could be the graph of f(x)?

Answer 1

Option A

Explanation:

Degree of the polynomial function = 4

That means highest degree term of the given polynomial has power = 4

If the roots of a quadratic polynomial are a, b, c, d then the polynomial function will be,

f(x) = (x - a)(x - b)(x - c)(x - d)

It's given in the question that roots are x = -2, -1, 1 and 3

Therefore, polynomial function will be,

f(x) = (x + 2)(x + 1)(x - 1)(x - 3)

From the given options, graph A shows that the graph intersects the x-axis at x = -2, -1, 1 and 3

Therefore, Option A will be the answer.