116k views
1 vote
Use synthetic division to divide f(x) = x^3 + 12x^2 + 41x + 30 by x + 5. Use the result to find all zeros of f.

A. {-5, 6, 1}
B. {-5, -6, -1}
C. {5, 6, 1}
D. {5, -6, -1}

1 Answer

6 votes

Final answer:

Using synthetic division and factoring, the zeros of the polynomial function f(x) = x^3 + 12x^2 + 41x + 30 are found to be -5, -6, and -1. The correct answer from the given options is B: {-5, -6, -1}.

Step-by-step explanation:

To use synthetic division to divide f(x) = x^3 + 12x^2 + 41x + 30 by x + 5, we first need to identify the zero of the divisor, which in this case is -5. Set up the synthetic division as follows:

  • Write down the coefficients of f(x): 1, 12, 41, 30.
  • Write the zero of the divisor outside the division symbol: -5.
  • Carry down the leading coefficient: 1.
  • Multiply -5 by 1 and write the result under the next coefficient: -5 * 1 = -5.
  • Add the second coefficient and the result: 12 + (-5) = 7.
  • Continue this process until you have processed all coefficients.

The synthetic division will look like this:

-5 | 1 12 41 30
| -5 -35 -30
-----------------
1 7 6 0

The result gives us a quotient of x^2 + 7x + 6 and a remainder of 0, indicating that -5 is a zero of f(x). Factor the quadratic to find the other zeros:

x^2 + 7x + 6 = (x + 6)(x + 1)

Therefore, the zeros are -5, -6, and -1. The correct answer is B: {-5, -6, -1}.

User Michael Sheaver
by
8.1k points