To divide the polynomial \( 12x^2 + 2x - 9 \) by \( 4x - 2 \), we can use polynomial long division.
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Divide the leading term of the dividend by the leading term of the divisor: \[ \frac{12x^2}{4x} = 3x \]
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Multiply the entire divisor by this result: \[ 3x(4x - 2) = 12x^2 - 6x \]
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Subtract this product from the original polynomial: \[ (12x^2 + 2x - 9) - (12x^2 - 6x) = 8x - 9 \]
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Repeat the process with the new polynomial \( 8x - 9 \):
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Divide the leading term: \[ \frac{8x}{4x} = 2 \]
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Multiply the divisor: \[ 2(4x - 2) = 8x - 4 \]
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Subtract again: \[ (8x - 9) - (8x - 4) = -5 \]
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Now we have completed the division, resulting in a quotient of \( 3x + 2 \) and a remainder of \( -5 \).
Thus, we can express the original polynomial as: \[ 12x^2 + 2x - 9 = (4x - 2)(3x + 2) - 5 \]
The correct answer is: \[ 12x^2 + 2x - 9 = (4x - 2)(3x + 2) - 5 \]