In Exercises 33–40, use synthetic division and the Remainder Theorem to find the indicated function value. f(x)=3x3−7x2−2x+5;f(−3)
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Identify the divisor for synthetic division based on the function value you want to find. Since you want to find f(−3), the divisor is x - (−3) or x + 3.
Set up synthetic division by writing the coefficients of the polynomial f(x) = 3x³ − 7x² − 2x + 5. These coefficients are 3, -7, -2, and 5.
Write the value −3 (from x + 3) to the left side of the synthetic division setup and bring down the first coefficient (3) as is.
Multiply −3 by the number just brought down (3), write the result under the next coefficient (-7), then add the column. Repeat this multiply and add process for each coefficient.
The final number you get after completing the synthetic division process is the remainder, which equals f(−3) by the Remainder Theorem.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Synthetic Division
Synthetic division is a shortcut method for dividing a polynomial by a linear binomial of the form (x - c). It simplifies the long division process by using only the coefficients of the polynomial, making calculations faster and less error-prone. This method is especially useful for evaluating polynomials and finding remainders.
The Remainder Theorem states that when a polynomial f(x) is divided by (x - c), the remainder is equal to f(c). This means you can find the value of the polynomial at x = c by performing synthetic division and looking at the remainder, providing a quick way to evaluate polynomials without direct substitution.
Polynomial evaluation involves finding the value of a polynomial function at a specific input value. Instead of substituting directly, synthetic division combined with the Remainder Theorem offers an efficient alternative to compute f(c), especially for higher-degree polynomials, by reducing computational complexity.