Use synthetic division to find the result when 3, x, cubed, minus, 10, x, squared, plus, 5, x, plus, 23x

3
−10x
2
+5x+2 is divided by x, minus, 1x−1.

1 answer

To perform synthetic division of the polynomial \(3x^3 - 10x^2 + 5x + 2\) by \(x - 1\), we can follow these steps:

  1. Write down the coefficients of the polynomial: \(3, -10, 5, 2\).
  2. Since we are dividing by \(x - 1\), we use \(1\) for synthetic division.
  3. Set up synthetic division by writing \(1\) on the left and the coefficients on the right:
1 | 3  -10   5   2
  |        
  1. Bring down the leading coefficient to the bottom row:
1 | 3  -10   5   2
  |        
  | 3
  1. Multiply the value just brought down \(3\) by \(1\) (the number we are dividing by) and write the result under the next coefficient:
1 | 3  -10   5   2
  |     3
  | 3  -7
  1. Add the numbers in the second column: \(-10 + 3 = -7\).
1 | 3  -10   5   2
  |     3  -7
  | 3  -7
  1. Repeat the process: multiply \(-7\) by \(1\) and write under the next coefficient \(5\):
1 | 3  -10  5  2
  |     3  -7
  | 3  -7  -2
  1. Add \(5 + (-7) = -2\):
1 | 3  -10  5  2
  |     3  -7  -2
  | 3  -7  -2
  1. Now multiply \(-2\) by \(1\) and write the result under \(2\):
1 | 3  -10  5  2
  |     3  -7  -2
  | 3  -7  -2
  1. Add the last column: \(2 + (-2) = 0\).

The final row gives you the coefficients of the resulting polynomial and the remainder.

The result of the synthetic division is:

\[ 3x^2 - 7x - 2 \]

with a remainder of \(0\).

Thus, \(3x^3 - 10x^2 + 5x + 2\) divided by \(x - 1\) is:

\[ 3x^2 - 7x - 2 \quad \text{with no remainder.} \]