Chapter 7: Problem 55
In Exercises \(51-62,\) evaluate each polynomial for the given values. $$6 x^{2}-7 x+3 \text { for } x=-\frac{1}{2}$$
Short Answer
Expert verified
8
Step by step solution
01
Substitute the given value
Substitute the value \(x = -\frac{1}{2}\) into the polynomial \(6x^2 - 7x + 3\).
02
Compute \(6x^2\)
Calculate \(6 \left(-\frac{1}{2}\right)^2\). First, compute \(\left(-\frac{1}{2}\right)^2 = \frac{1}{4}\). Then, multiply this by 6 to get \(6 \times \frac{1}{4} = \frac{6}{4} = \frac{3}{2}\).
03
Compute \(-7x\)
Calculate \(-7 \left(-\frac{1}{2}\right)\). Multiply to get \(-7 \times -\frac{1}{2} = \frac{7}{2}\).
04
Add the constant term
The constant term is 3. So, you have \(\frac{3}{2} + \frac{7}{2} + 3\).
05
Perform the addition
Combine the fractions and the constant term: \(\frac{3}{2} + \frac{7}{2} = \frac{10}{2} = 5\). Then, add 3 to get \(5 + 3 = 8\).
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
substitution method
The substitution method is a technique used to replace variables with given values. This allows us to evaluate expressions or polynomials effectively. In our exercise, we are given the polynomial \(6x^2 - 7x + 3\) and need to find its value when \(x = -\frac{1}{2}\). To do this using the substitution method:
- Identify the given value you need to substitute.
- Replace every occurrence of the variable in the polynomial with this value.
- Proceed to simplify and calculate the final result. By replacing \(x\) with \(-\frac{1}{2}\) in the polynomial, we'll perform calculations to eventually reach the solution.
polynomial evaluation
Polynomial evaluation is the process of determining the value of a polynomial function for a given value of its variable(s). In mathematical terms, given a polynomial \(P(x) = 6x^2 - 7x + 3\), we can find \(P(-\frac{1}{2})\) by substituting \(x = -\frac{1}{2}\). Here's how to carry out polynomial evaluation:
- After substituting the given value, follow arithmetic operations strictly according to the order of operations (PEMDAS/BODMAS rules).
- Begin with exponents, then proceed to multiplication and division from left to right.
- Finally, complete addition and subtraction operations. By carefully following these steps, you ensure accurate results in polynomial evaluation.
simplifying fractions
Simplifying fractions plays a key role in evaluating polynomials, especially when dealing with fractional values. During our exercise, you will encounter fractions throughout the simplification process. The steps are clear:
- Complete multiplication/division as necessary before simplifying.
- Look for common factors in the numerator and denominator to reduce the fraction.
- Convert complex fractions into simpler terms when adding or subtracting. For example, when calculating \(6 \times (-\frac{1}{2})^2\), we computed \((-\frac{1}{2})^2 = \frac{1}{4}\), then multiplied it by 6 to get \(\frac{6}{4} = \frac{3}{2}\). Breaking fractions down accurately helps avoid mistakes and streamline calculations.
basic algebra steps
Basic algebra forms the groundwork for solving polynomial evaluations and includes several fundamental steps:
- Identify and substitute values correctly to start computations.
- Adhere to order of operations, simplifying exponents and performing arithmetic in sequence.
- Simplify fractions by finding common denominators and reducing them correctly. Integrating all these steps proves vital in our example. Substituting \(x = -\frac{1}{2}\):
- First, calculate \(6(-\frac{1}{2})^2 = \frac{3}{2}\).
- Then, compute \(-7(-\frac{1}{2}) = \frac{7}{2}\).
- Finally, add up \(\frac{3}{2} + \frac{7}{2} + 3 = 8\). Understanding these basic algebra steps ensures a solid foundation for evaluating more complex expressions.