What is the result of using synthetic division to divide 3x4−5x3+4x2−7x+1

by x+1
?(1 point)
Responses

3x3−8x2+12x−19+20x+1
3 x cubed minus 8 x squared plus 12 x minus 19 plus the fraction with numerator 20 and denominator x plus 1

3x3−8x2+12x−8
3 x cubed minus 8 x squared plus 12 x minus 8

3x3−8x2+12x−8−7x+1
3 x cubed minus 8 x squared plus 12 x minus 8 minus the fraction with numerator 7 and denominator x plus 1

3x3−2x2+2x−5−4x+1

1 answer

To use synthetic division to divide \(3x^4 - 5x^3 + 4x^2 - 7x + 1\) by \(x + 1\), we will substitute \(-1\) for \(x\) in synthetic division (since we set \(x + 1 = 0\) giving \(x = -1\)).

Here are the steps:

  1. Write down the coefficients of the polynomial:
    \(3, -5, 4, -7, 1\)

  2. Set up synthetic division using \(-1\):

-1 | 3   -5   4   -7   1
   |      -3   8   -12   19
   ----------------
      3   -8   12   -19   20
  1. Bring down the first coefficient \(3\).

  2. Multiply \(-1\) by \(3\) and write the result underneath \(-5\): \(-1 \times 3 = -3\).

  3. Add \(-5\) and \(-3\) to get \(-8\).

  4. Repeat the process:

    • Multiply \(-1\) by \(-8\) to get \(8\), and add to \(4\): \(4 + 8 = 12\).
    • Multiply \(-1\) by \(12\) to get \(-12\), and add to \(-7\): \(-7 - 12 = -19\).
    • Multiply \(-1\) by \(-19\) to get \(19\), and add to \(1\): \(1 + 19 = 20\).
  5. The result of the synthetic division is therefore:

    • Quotient: \(3x^3 - 8x^2 + 12x - 19\)
    • Remainder: \(20\)

So, we can write the result as: \[3x^3 - 8x^2 + 12x - 19 + \frac{20}{x + 1}\]

Thus, the correct response is: 3x^3−8x^2+12x−19+20/(x+1).