Math Problem Statement

Use the remainder theorem to find P(3) for P(x) = -x^3 + 4x^2 + 8. Specifically, give the quotient and the remainder for the associated division and the value of P(3).

Solution

The task here involves using the remainder theorem to find the value of P(3)P(3) for the polynomial P(x)=x3+4x2+8P(x) = -x^3 + 4x^2 + 8, as well as the quotient and the remainder from dividing the polynomial by x3x - 3.

Steps to solve the problem:

  1. Apply the remainder theorem:
    The remainder theorem tells us that the remainder of the division of a polynomial P(x)P(x) by xax - a is P(a)P(a). Here, we are dividing by x3x - 3, so the remainder will be P(3)P(3).

  2. Evaluate P(3)P(3): P(3)=(3)3+4(3)2+8P(3) = -(3)^3 + 4(3)^2 + 8 Simplifying step by step: P(3)=(27)+4(9)+8P(3) = -(27) + 4(9) + 8 P(3)=27+36+8=17P(3) = -27 + 36 + 8 = 17

    So, P(3)=17P(3) = 17. This value is also the remainder.

  3. Find the quotient:
    To find the quotient, we need to perform polynomial division of P(x)=x3+4x2+8P(x) = -x^3 + 4x^2 + 8 by x3x - 3.

    Using synthetic division:

    • Write the coefficients of P(x)P(x): [-1, 4, 0, 8].
    • Use x3x - 3, so the root is 3.

    Perform synthetic division:

    3 | -1   4   0   8
        |      -3   3   9
        ----------------
         -1   1   3   17
    

    The quotient is x2+x+3-x^2 + x + 3, and the remainder is 17 (which matches P(3)P(3)).

Final Answer:

  • Quotient: x2+x+3-x^2 + x + 3
  • Remainder: 17
  • P(3)P(3) = 17

Would you like more details on synthetic division or have any other questions?

Here are 5 related questions for further practice:

  1. How do you perform polynomial division using the long division method?
  2. What does the remainder theorem state and how is it useful?
  3. Can the quotient be factored further in certain division problems?
  4. How do synthetic division and long division compare in efficiency?
  5. How would the process change if you divided by a different xax - a?

Tip: Always verify your quotient by multiplying it back with the divisor and adding the remainder to check if it matches the original polynomial.

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Math Problem Analysis

Mathematical Concepts

Algebra
Polynomial Division
Remainder Theorem
Synthetic Division

Formulas

Remainder Theorem: If a polynomial P(x) is divided by (x - a), the remainder is P(a).
Synthetic Division Process

Theorems

Remainder Theorem

Suitable Grade Level

Grades 9-12