Math Problem Statement

Use the remainder theorem to find P(-1) for P(x)=x3+4x2+7P\left(x\right)=x^3+4x^2+7

Solution

To find P(1)P(-1) for the polynomial P(x)=x3+4x2+7P(x) = x^3 + 4x^2 + 7 using the Remainder Theorem, we follow these steps:

The Remainder Theorem states that if a polynomial P(x)P(x) is divided by xax - a, the remainder of this division is P(a)P(a). Thus, to find P(1)P(-1), we can simply substitute x=1x = -1 into the polynomial.

Given: P(x)=x3+4x2+7P(x) = x^3 + 4x^2 + 7

Substitute x=1x = -1: P(1)=(1)3+4(1)2+7P(-1) = (-1)^3 + 4(-1)^2 + 7

Now, calculate each term: (1)3=1(-1)^3 = -1 4(1)2=41=44(-1)^2 = 4 \cdot 1 = 4 7 remains as it is7 \text{ remains as it is}

Combine the results: P(1)=1+4+7P(-1) = -1 + 4 + 7 P(1)=10P(-1) = 10

Therefore, P(1)=10P(-1) = 10.

Would you like any more details or have any questions?

Here are some related questions for further exploration:

  1. What is the Remainder Theorem?
  2. How can you use the Remainder Theorem to determine the roots of a polynomial?
  3. What is the value of P(2)P(2) for the same polynomial?
  4. How would you apply the Factor Theorem to P(x)=x3+4x2+7P(x) = x^3 + 4x^2 + 7?
  5. What are synthetic division and how does it relate to the Remainder Theorem?
  6. How do you factorize a cubic polynomial?
  7. What are the roots of P(x)=x3+4x2+7P(x) = x^3 + 4x^2 + 7?
  8. How do you graph the polynomial P(x)=x3+4x2+7P(x) = x^3 + 4x^2 + 7?

Tip: Always check if you can factorize a polynomial to simplify the evaluation process.