Math  /  Algebra

QuestionEvaluate the polynomial function using Synthetic Division f(x)=5x3+3x2x+7 when x=2\begin{array}{c} f(x)=5 x^{3}+3 x^{2}-x+7 \\ \text { when } x=2 \end{array}

Studdy Solution

STEP 1

1. We are given the polynomial function f(x)=5x3+3x2x+7 f(x) = 5x^3 + 3x^2 - x + 7 .
2. We need to evaluate the polynomial at x=2 x = 2 using synthetic division.

STEP 2

1. Set up the synthetic division.
2. Perform the synthetic division.
3. Interpret the result to find f(2) f(2) .

STEP 3

Write down the coefficients of the polynomial: 5,3,1,7 5, 3, -1, 7 .
Set up the synthetic division with x=2 x = 2 as the divisor:
25317\begin{array}{c|cccc} 2 & 5 & 3 & -1 & 7 \\ & & & & \\ \end{array}

STEP 4

Bring down the leading coefficient (5):
253175\begin{array}{c|cccc} 2 & 5 & 3 & -1 & 7 \\ & & & & \\ & 5 & & & \\ \end{array}
Multiply the divisor (2) by the number just written below the line (5), and write the result (10) under the next coefficient (3):
25317105\begin{array}{c|cccc} 2 & 5 & 3 & -1 & 7 \\ & & 10 & & \\ & 5 & & & \\ \end{array}
Add the numbers in the second column:
2531710513\begin{array}{c|cccc} 2 & 5 & 3 & -1 & 7 \\ & & 10 & & \\ & 5 & 13 & & \\ \end{array}

STEP 5

Repeat the process: Multiply the divisor (2) by the new number below the line (13), and write the result (26) under the next coefficient (-1):
253171026513\begin{array}{c|cccc} 2 & 5 & 3 & -1 & 7 \\ & & 10 & 26 & \\ & 5 & 13 & & \\ \end{array}
Add the numbers in the third column:
25317102651325\begin{array}{c|cccc} 2 & 5 & 3 & -1 & 7 \\ & & 10 & 26 & \\ & 5 & 13 & 25 & \\ \end{array}

STEP 6

Repeat the process one more time: Multiply the divisor (2) by the new number below the line (25), and write the result (50) under the next coefficient (7):
2531710265051325\begin{array}{c|cccc} 2 & 5 & 3 & -1 & 7 \\ & & 10 & 26 & 50 \\ & 5 & 13 & 25 & \\ \end{array}
Add the numbers in the fourth column:
253171026505132557\begin{array}{c|cccc} 2 & 5 & 3 & -1 & 7 \\ & & 10 & 26 & 50 \\ & 5 & 13 & 25 & 57 \\ \end{array}

STEP 7

The last number (57) is the remainder and represents the value of f(2) f(2) .
Thus, f(2)=57 f(2) = 57 .
The value of f(2) f(2) is:
57 \boxed{57}

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