Question

A polynomial function has a root of -5 with multiplicity 3, a root of 1 with multiplicity of 2, and a root of 3 with multiplicity 7.

If the function has a negative leading coefficient and is of even degree which statement about the graph is true?

a) function is positive on (-∞,-5)
b) fuction is negative on (-5,3)
c) function is positive on (-∞,1)
d) function is negative on (3,∞)​

Answer 1

The graph of the function is positive on (-co, -5).

The graph of the function is negative on (3,co).

Step-by-step explanation:

We know that the roots are in: -5, 1 and 3.

and after 3, the graph is in the negative side, so between 1 and 3 the graph must be in the positive side, between -5 and 1 the graph must be in the negative side, and between -inifinity and -5 the graph must be in the positive side:

So the statements that are true are:

The graph of the function is positive on (-co, -5).

The graph of the function is negative on (3,co).

Answer 2

d) function is negative on (3,∞)​

Explanation:

The even degree and negative leading coefficient tell you that the function is negative as x ⇒ ±∞. (Selections A and C cannot be correct.)

The odd multiplicity tells you the function crosses the x-axis at x=-5 and x=3, so will be non-negative between those values. (Selection B cannot be correct.)

The function is negative on (3, ∞).