Math Problem Statement

If (x - 2) and x are the factors of the polynomial 2x^3 - 5x^2 + ax + b, then find the values of a and b.

Solution

The question requires us to find the values of aa and bb such that the polynomial 2x35x2+ax+b2x^3 - 5x^2 + ax + b has (x2)(x - 2) and xx as its factors. Here's the step-by-step solution:

Step 1: Understanding the Problem

If (x2)(x - 2) and xx are factors of the polynomial, then the polynomial must satisfy:

  1. P(2)=0P(2) = 0
  2. P(0)=0P(0) = 0

Here, P(x)=2x35x2+ax+bP(x) = 2x^3 - 5x^2 + ax + b.

Step 2: Substitute x=0x = 0

From P(0)=0P(0) = 0: P(0)=2(0)35(0)2+a(0)+b=bP(0) = 2(0)^3 - 5(0)^2 + a(0) + b = b This implies: b=0b = 0

Step 3: Substitute x=2x = 2

From P(2)=0P(2) = 0: P(2)=2(2)35(2)2+a(2)+b=0P(2) = 2(2)^3 - 5(2)^2 + a(2) + b = 0 Substitute b=0b = 0: P(2)=2(8)5(4)+2a=0P(2) = 2(8) - 5(4) + 2a = 0 Simplify: 1620+2a=016 - 20 + 2a = 0 4+2a=0-4 + 2a = 0 2a=42a = 4 a=2a = 2

Final Answer

The values of aa and bb are: a=2,b=0a = 2, \quad b = 0


Would you like further details or have any questions about the solution?
Here are some related questions to consider:

  1. How do we determine the factors of a polynomial?
  2. What is the significance of setting P(x)=0P(x) = 0 for the factors of a polynomial?
  3. Can there be more than two factors for a cubic polynomial?
  4. How would the solution change if (x2)(x - 2) was not a factor?
  5. How can synthetic division help verify (x2)(x - 2) as a factor?

Tip: Always test each potential factor by substituting its root into the polynomial. This ensures the correctness of your calculations!

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Math Problem Analysis

Mathematical Concepts

Polynomials
Roots and Factors
Factor Theorem

Formulas

P(c) = 0 if (x - c) is a factor of P(x)
Substitution of roots into a polynomial

Theorems

Factor Theorem

Suitable Grade Level

Grades 10-12