Chapter 5: Problem 59
Evaluate polynomial for \(x=3\) and for \(x=-3\). \(-2 x^{3}-3 x^{2}+4 x+2\)
Short Answer
Expert verified
When x = 3, the polynomial evaluates to -67. When x = -3, it evaluates to 17.
Step by step solution
01
Identify the Polynomial
The given polynomial to evaluate is a(x) = -2x^3 - 3x^2 + 4x + 2
02
Substitute x = 3 into the Polynomial
Replace x with 3 in the polynomial: a(3) = -2(3)^3 - 3(3)^2 + 4(3) + 2
03
Calculate Each Term for x = 3
Evaluate each term individually: -2(3)^3 = -2(27) = -54, -3(3)^2 = -3(9) = -27, 4(3) = 12, and simply 2 Thus: a(3) = -54 - 27 + 12 + 2
04
Add the Results for x = 3
Sum the evaluated terms: -54 - 27 + 12 + 2 = -67
05
Substitute x = -3 into the Polynomial
Replace x with -3 in the polynomial: a(-3) = -2(-3)^3 - 3(-3)^2 + 4(-3) + 2
06
Calculate Each Term for x = -3
Evaluate each term individually: -2(-3)^3 = -2(-27) = 54, -3(-3)^2 = -3(9) = -27, 4(-3) = -12, and simply 2 Thus: a(-3) = 54 - 27 - 12 + 2
07
Add the Results for x = -3
Sum the evaluated terms: 54 - 27 - 12 + 2 = 17
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Polynomial Evaluation
Polynomial evaluation is the process of calculating the value of a polynomial function at a particular point. Polynomials are expressions consisting of variables and coefficients, combined using addition, subtraction, and multiplication. In this exercise, we evaluate the polynomiala(x) = -2x^3 - 3x^2 + 4x + 2at two different points, x = 3 and x = -3. This helps us see how the polynomial behaves at these specific values.
To evaluate the given polynomial, we need to substitute the value of x into the polynomial and simplify the expression step-by-step, as shown in the provided solution.
Let's break down the process in the upcoming sections to ensure a clearer understanding.
To evaluate the given polynomial, we need to substitute the value of x into the polynomial and simplify the expression step-by-step, as shown in the provided solution.
Let's break down the process in the upcoming sections to ensure a clearer understanding.
Substitution Method
The substitution method in polynomial evaluation involves replacing the variable x with a given numerical value. This allows us to calculate the polynomial's value at that specific point.
The steps are straightforward:
The steps are straightforward:
- Identify the polynomial expression, which in our case is a(x) = -2x^3 - 3x^2 + 4x + 2.
- Replace x with the given value.
- Calculate each term individually by following the order of operations (PEMDAS/BODMAS).
- Replace x with 3: a(3) = -2(3)^3 - 3(3)^2 + 4(3) + 2.
- Calculate each term: -2(3)^3 = -54, -3(3)^2 = -27, 4(3) = 12, and 2 remains as 2.
- Add the results: -54 - 27 + 12 + 2 = -67.
Algebraic Calculation
Algebraic calculation in polynomial evaluation involves systematically simplifying the polynomial after substitution. Each term is calculated by following mathematical rules of operations.
Let's evaluate the same polynomial for x = -3:
Let's evaluate the same polynomial for x = -3:
- First, substitute -3 into the polynomial: a(-3) = -2(-3)^3 - 3(-3)^2 + 4(-3) + 2.
- Next, calculate each term: -2(-3)^3 = 54, -3(-3)^2 = -27, 4(-3) = -12, and 2 remains 2.
- Finally, sum the evaluated terms: 54 - 27 - 12 + 2 = 17.