Determine the possible rational zeros of this polynomial function using the rational zeros theorem: p(x) = 4x^4 + 13x^3 – 49x^2 – 73x –15

Respuesta :

Answer:

[tex]\large \boxed{\sf \ \ \ -1, \ -5, \ -\dfrac{1}{4} \ \ \ }[/tex]

Step-by-step explanation:

Hello,

Let's determine the possible rational zeros of this polynomial function using the rational zeros theorem:

[tex]P(x) = 4x^4 + 13x^3-49x^2-73x-15[/tex]

First of all, what is the rational zeroes theorem?

If P(x) is a polynomial with integer coefficients

and if (p and q being integer)

[tex]\dfrac{p}{q}[/tex]

is a zero of P(x), meaning

[tex]P(\dfrac{p}{q})=0[/tex]

then p is a factor of the constant term of P(x) and

q is a factor of the leading coefficient of P(x).

How to apply it here?

The constant term of P(x) is -15

The leading coefficient of P(x) is 4

so p is a factor of -15

q is a factor of 4

15 = 1 * 5 * 3

4 = 2 * 2 * 1

q can be 1, 2, 4

-p can be 1, 3, 5, 15

so it gives the following potential solutions

-1, -3, -5, -15

[tex]\dfrac{-1}{2}, \dfrac{-3}{2}, \dfrac{-5}{2}, \dfrac{-15}{2}[/tex]

[tex]\dfrac{-1}{4}, \dfrac{-3}{4}, \dfrac{-5}{4}, \dfrac{-15}{4}[/tex]

Let's compute P(x) for x in this list of potential solutions

x P(x)

-1 0

-3 -264

-5 0

-15 148680

-0.5 7.875

-1.5 -39.375

-2.5 -185.625

-7.5 4948.125

-0.25 0

-0.75 7.96875

-1.25 -15.9375

-3.75 -324.84375

It gives -1, -5 and -0.25

Conclusion

The possible rational zeroes of P(x) are

-1

-5

[tex]\dfrac{-1}{4}[/tex]

Hope this helps.

Do not hesitate if you need further explanation.

Thank you