Polynomial Long Division: (x³ + 5x² + 5x - 2) ÷ (x + 2)
This article will walk through the process of dividing the polynomial (x³ + 5x² + 5x - 2) by (x + 2) using polynomial long division.
Setting up the Division
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Write the dividend and divisor in a long division format.
____________ x + 2 | x³ + 5x² + 5x - 2
Performing the Division
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Divide the leading term of the dividend (x³) by the leading term of the divisor (x). This gives us x².
x²_________ x + 2 | x³ + 5x² + 5x - 2
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Multiply the quotient (x²) by the divisor (x + 2). This gives us x³ + 2x².
x²_________ x + 2 | x³ + 5x² + 5x - 2 x³ + 2x²
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Subtract the result from the dividend.
x²_________ x + 2 | x³ + 5x² + 5x - 2 x³ + 2x² --------- 3x²
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Bring down the next term of the dividend (5x).
x²_________ x + 2 | x³ + 5x² + 5x - 2 x³ + 2x² --------- 3x² + 5x
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Repeat steps 1-4.
- Divide the leading term of the new dividend (3x²) by the leading term of the divisor (x). This gives us 3x.
- Multiply the quotient (3x) by the divisor (x + 2). This gives us 3x² + 6x.
- Subtract the result.
- Bring down the next term (-2).
x² + 3x______ x + 2 | x³ + 5x² + 5x - 2 x³ + 2x² --------- 3x² + 5x 3x² + 6x --------- -x - 2
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Repeat steps 1-4 again.
- Divide the leading term of the new dividend (-x) by the leading term of the divisor (x). This gives us -1.
- Multiply the quotient (-1) by the divisor (x + 2). This gives us -x - 2.
- Subtract the result.
x² + 3x - 1_ x + 2 | x³ + 5x² + 5x - 2 x³ + 2x² --------- 3x² + 5x 3x² + 6x --------- -x - 2 -x - 2 ------- 0
The Result
We have reached a remainder of zero, which means the division is complete. Therefore, (x³ + 5x² + 5x - 2) ÷ (x + 2) = x² + 3x - 1.
In other words, (x³ + 5x² + 5x - 2) can be factored as (x + 2)(x² + 3x - 1).