IDNLearn.com provides a user-friendly platform for finding and sharing accurate answers. Our platform is designed to provide trustworthy and thorough answers to any questions you may have.

Which of the numbers below are potential roots of [tex]$p(x)=x^3+6x^2-7x-60$[/tex] according to the Rational Root Theorem?

A. -10
B. -7
C. -5
D. 3
E. 15
F. 24


Sagot :

To determine which of the given numbers are potential roots of the polynomial [tex]\( p(x) = x^3 + 6x^2 - 7x - 60 \)[/tex] according to the rational root theorem, we need to follow these steps:

1. List the Potential Roots Using the Rational Root Theorem:
The rational root theorem tells us that any rational root of the polynomial [tex]\( p(x) \)[/tex] will be a factor of the constant term divided by a factor of the leading coefficient. For the polynomial [tex]\( p(x) = x^3 + 6x^2 - 7x - 60 \)[/tex]:
- The constant term is [tex]\(-60\)[/tex].
- The leading coefficient (coefficient of [tex]\( x^3 \)[/tex]) is [tex]\( 1 \)[/tex].

Factors of [tex]\(-60\)[/tex] include: [tex]\(\pm 1, \pm 2, \pm 3, \pm 4, \pm 5, \pm 6, \pm 10, \pm 12, \pm 15, \pm 20, \pm 30, \pm 60\)[/tex].
Since the leading coefficient is [tex]\(1\)[/tex], we consider these factors as potential rational roots.

2. Evaluate Each Given Potential Root:
We now evaluate the polynomial at each of the given numbers to see which ones are actual roots (i.e., [tex]\( p(x) = 0 \)[/tex]).

- For [tex]\( x = -10 \)[/tex]:
[tex]\[ p(-10) = (-10)^3 + 6(-10)^2 - 7(-10) - 60 = -1000 + 600 + 70 - 60 = -390 \neq 0 \][/tex]
- For [tex]\( x = -7 \)[/tex]:
[tex]\[ p(-7) = (-7)^3 + 6(-7)^2 - 7(-7) - 60 = -343 + 294 + 49 - 60 = -60 \neq 0 \][/tex]
- For [tex]\( x = -5 \)[/tex]:
[tex]\[ p(-5) = (-5)^3 + 6(-5)^2 - 7(-5) - 60 = -125 + 150 + 35 - 60 = 0 \][/tex]
Hence, [tex]\( x = -5 \)[/tex] is a root of [tex]\( p(x) \)[/tex].
- For [tex]\( x = 3 \)[/tex]:
[tex]\[ p(3) = 3^3 + 6(3)^2 - 7(3) - 60 = 27 + 54 - 21 - 60 = 0 \][/tex]
Hence, [tex]\( x = 3 \)[/tex] is a root of [tex]\( p(x) \)[/tex].
- For [tex]\( x = 15 \)[/tex]:
[tex]\[ p(15) = 15^3 + 6(15)^2 - 7(15) - 60 = 3375 + 1350 - 105 - 60 = 4560 \neq 0 \][/tex]
- For [tex]\( x = 24 \)[/tex]:
[tex]\[ p(24) = 24^3 + 6(24)^2 - 7(24) - 60 = 13824 + 3456 - 168 - 60 = 16926 \neq 0 \][/tex]

3. Conclusion:
From the evaluation above, we find that the numbers [tex]\(-5\)[/tex] and 3 are roots of the polynomial [tex]\( p(x) = x^3 + 6x^2 - 7x - 60 \)[/tex].

Thus, the numbers among the given options that are potential roots of the polynomial are:
[tex]\[ -5 \quad \text{and} \quad 3. \][/tex]