Math Problem Statement

Polynomial ax^4 - 13x^3 + 27x^2 - 38x + b has a factor x^2 - 6x + 8. Find the value of a + b.

Solution

The problem in the image involves a polynomial ax413x3+27x238x+bax^4 - 13x^3 + 27x^2 - 38x + b which has a factor of x26x+8x^2 - 6x + 8. We are asked to find the value of a+ba + b.

Step-by-step solution:

  1. Factor of the Polynomial: The polynomial is divisible by x26x+8x^2 - 6x + 8, which can be factored further as: x26x+8=(x2)(x4)x^2 - 6x + 8 = (x - 2)(x - 4) This tells us that x=2x = 2 and x=4x = 4 are roots of the polynomial.

  2. Using Root Substitution: Since x=2x = 2 is a root, substitute x=2x = 2 into the polynomial ax413x3+27x238x+bax^4 - 13x^3 + 27x^2 - 38x + b and set it equal to 0: a(2)413(2)3+27(2)238(2)+b=0a(2)^4 - 13(2)^3 + 27(2)^2 - 38(2) + b = 0 Simplifying this: 16a13(8)+27(4)38(2)+b=016a - 13(8) + 27(4) - 38(2) + b = 0 16a104+10876+b=016a - 104 + 108 - 76 + b = 0 16a+b72=016a + b - 72 = 0 Therefore, we have the first equation: 16a+b=72(Equation 1)16a + b = 72 \quad \text{(Equation 1)}

  3. Using the Second Root: Now, substitute x=4x = 4 into the polynomial: a(4)413(4)3+27(4)238(4)+b=0a(4)^4 - 13(4)^3 + 27(4)^2 - 38(4) + b = 0 Simplifying this: 256a13(64)+27(16)38(4)+b=0256a - 13(64) + 27(16) - 38(4) + b = 0 256a832+432152+b=0256a - 832 + 432 - 152 + b = 0 256a+b552=0256a + b - 552 = 0 Therefore, we have the second equation: 256a+b=552(Equation 2)256a + b = 552 \quad \text{(Equation 2)}

  4. Solving the System of Equations: We now have two equations:

    1. 16a+b=7216a + b = 72
    2. 256a+b=552256a + b = 552

    Subtract Equation 1 from Equation 2: (256a+b)(16a+b)=55272(256a + b) - (16a + b) = 552 - 72 Simplifying: 240a=480240a = 480 a=2a = 2

  5. Finding bb: Substitute a=2a = 2 into Equation 1: 16(2)+b=7216(2) + b = 72 32+b=7232 + b = 72 b=40b = 40

  6. Calculating a+ba + b: a+b=2+40=42a + b = 2 + 40 = 42

Thus, the value of a+ba + b is 42\boxed{42}.


Would you like more details or have any questions about this solution? Here are 5 related questions you could explore:

  1. How do we check if a polynomial is divisible by another polynomial?
  2. What happens if a polynomial has more than one factor, such as quadratic and linear factors?
  3. Can a polynomial have a root at x=0x = 0 without an explicit constant term?
  4. How does synthetic division work for factoring higher-degree polynomials?
  5. What are the methods for solving systems of equations involving polynomials?

Tip: Always double-check your factorization of polynomials to ensure that you are working with the correct roots and factors!

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Math Problem Analysis

Mathematical Concepts

Polynomial division
Factoring
Algebra

Formulas

Polynomial division: f(x) = (x - root1)(x - root2)
Substitute root values into polynomial to solve for a and b

Theorems

Factor Theorem

Suitable Grade Level

Grades 10-12