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select the correct answer. one factor of the polynomial $2x^3 - 3x^2 - …

Question

select the correct answer.
one factor of the polynomial $2x^3 - 3x^2 - 3x + 2$ is $(x - 2)$. which expression represents the other factor, or factors, of the polynomial?
\\(\bigcirc\\) a. \\((2x + 1)(x - 1)\\)
\\(\bigcirc\\) b. \\((2x - 1)(x + 1)\\)
\\(\bigcirc\\) c. \\((2x^2 - x + 1)\\)
\\(\bigcirc\\) d. \\((2x^2 + 1)\\)

Explanation:

Step1: Perform Polynomial Division or Use Synthetic Division

We can divide the polynomial \(2x^3 - 3x^2 - 3x + 2\) by \((x - 2)\) using polynomial long division or synthetic division. Let's use synthetic division. The root for \((x - 2)\) is \(x = 2\).

Set up synthetic division:

$$ LATEXBLOCK0 $$

The quotient polynomial is \(2x^2 + x - 1\).

Step2: Factor the Quotient Polynomial

Now, factor \(2x^2 + x - 1\). We need two numbers that multiply to \(2\times(-1)= -2\) and add to \(1\). The numbers are \(2\) and \(-1\).

Rewrite the middle term: \(2x^2 + 2x - x - 1\)

Group and factor:

$$ LATEXBLOCK1 $$

Wait, no, wait. Wait, when we did synthetic division, the coefficients were 2, 1, -1, so the quotient is \(2x^2 + x - 1\). Wait, let's check the factoring again. Wait, maybe I made a mistake. Wait, let's use the quadratic formula on \(2x^2 + x - 1\). The quadratic formula is \(x=\frac{-b\pm\sqrt{b^2 - 4ac}}{2a}\) for \(ax^2+bx+c\). Here, \(a = 2\), \(b = 1\), \(c = -1\).

$$ x=\frac{-1\pm\sqrt{1 + 8}}{4}=\frac{-1\pm3}{4} $$

So \(x=\frac{-1 + 3}{4}=\frac{2}{4}=\frac{1}{2}\) and \(x=\frac{-1 - 3}{4}=\frac{-4}{4}=-1\). So the factors are \((x - \frac{1}{2})(x + 1)\), but to eliminate the fraction, multiply by 2: \((2x - 1)(x + 1)\). Wait, but let's check by multiplying \((x - 2)(2x - 1)(x + 1)\).

First, multiply \((2x - 1)(x + 1)=2x^2 + 2x - x - 1 = 2x^2 + x - 1\). Then multiply by \((x - 2)\):

$$ LATEXBLOCK2 $$

Which matches the original polynomial. Wait, but let's check the options. Option A is \((2x + 1)(x - 1)\), Option B is \((2x - 1)(x + 1)\), Option C is \(2x^2 - x + 1\), Option D is \(2x^2 + 1\).

Wait, maybe I made a mistake in synthetic division. Let's try polynomial long division. Divide \(2x^3 - 3x^2 - 3x + 2\) by \(x - 2\).

$$ LATEXBLOCK3 $$

So the quotient is \(2x^2 + x - 1\), which factors to \((2x - 1)(x + 1)\) as we did before. Wait, but let's check the options again. Option B is \((2x - 1)(x + 1)\), which is the correct factorization of the quotient. Wait, but let's check by multiplying \((x - 2)(2x - 1)(x + 1)\) as we did, which gives the original polynomial. So the other factor is \((2x - 1)(x + 1)\), which is option B.

Wait, but let's check the options again. Option A: \((2x + 1)(x - 1)=2x^2 - 2x + x - 1=2x^2 - x - 1\), which is different. Option B: \((2x - 1)(x + 1)=2x^2 + 2x - x - 1=2x^2 + x - 1\), which is the quotient. So the correct answer is B.

Answer:

B. \((2x - 1)(x + 1)\)