Chapter 5: Problem 57
Evaluate polynomial for \(x=3\) and for \(x=-3\). \(2 x^{2}-3 x+7\)
Short Answer
Expert verified
The value is 16 for x = 3 and 34 for x = -3.
Step by step solution
01
Understand the Polynomial
The given polynomial is 2x^2 - 3x + 7.
02
Substitute x = 3
First, substitute x = 3 into the polynomial. Calculate 2(3)^2 - 3(3) + 7.
03
Calculate Each Term for x = 3
Calculate the value of each term: 2(3)^2 = 18, -3(3) = -9, and add 7.
04
Sum the Results for x = 3
Now find the sum: 18 - 9 + 7. The result is 16.
05
Substitute x = -3
Next, substitute x = -3 into the polynomial. Calculate 2(-3)^2 - 3(-3) + 7.
06
Calculate Each Term for x = -3
Calculate the value of each term: 2(-3)^2 = 18, -3(-3) = 9, and add 7.
07
Sum the Results for x = -3
Finally, find the sum: 18 + 9 + 7. The result is 34.
Unlock Step-by-Step Solutions & Ace Your Exams!
-
Full Textbook Solutions
Get detailed explanations and key concepts
-
Unlimited Al creation
Al flashcards, explanations, exams and more...
-
Ads-free access
To over 500 millions flashcards
-
Money-back guarantee
We refund you if you fail your exam.
Over 30 million students worldwide already upgrade their learning with 91Ó°ÊÓ!
Key Concepts
These are the key concepts you need to understand to accurately answer the question.
substitution method
The substitution method is a way to evaluate polynomials by replacing the variable with a given number. In our exercise, this method involves substituting the values 3 and -3 into the polynomial. This means wherever you see the variable x in the polynomial, you replace it with the given number. For example, replacing x with 3 in the polynomial 2x^2 - 3x + 7 results in 2(3)^2 - 3(3) + 7. This process helps you convert the expression into a numerical calculation, simplifying the evaluation.
polynomials
A polynomial is a mathematical expression consisting of variables, coefficients, and exponents. In our case, the polynomial is 2x^2 - 3x + 7. Polynomials are made up of terms, which are separated by plus (+) or minus (-) signs. Each term includes a coefficient (like 2 or -3), a variable (like x), and an exponent (like 2 in x^2). Polynomials can represent a wide variety of mathematical relationships and are used frequently in algebra and calculus. Understanding polynomials is key to solving many types of math problems.
simplification
Simplification involves reducing a mathematical expression to its simplest form. For polynomials, this means combining like terms and performing arithmetic operations to get a single, simplified expression. In our example, after substituting x with 3 or -3, we simplified each term individually. For x = 3, calculate each term: 2(3)^2 becomes 18, -3(3) becomes -9, and adding 7 remains 7. Finally, sum the results (18 - 9 + 7). For x = -3, perform the same steps. Simplification makes it easier to evaluate and understand the polynomial.
exponents
Exponents are a way to represent repeated multiplication of the same number. In the polynomial 2x^2 - 3x + 7, the exponent 2 in x^2 indicates that x is multiplied by itself: x*x. Evaluating exponents is an important step in polynomial evaluation. For example, with x = 3, x^2 becomes 3*3, which equals 9. Then, multiply by the coefficient: 2(3^2) becomes 2*9, which is 18. Understanding how to work with exponents helps you accurately evaluate each term of the polynomial.