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Please explain and help. Thank you in advance

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1 Answer

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Using Vieta's formulas, we have:

$$ \begin{eqnarray} a+b &=& -\frac{-3}{2} = \frac{3}{2}\\ ab &=& \frac{-6}{2} = -3 \end{eqnarray} $$

So:

$$ \begin{eqnarray} (a+2)(b+2) &=& ab + 2a + 2b + 4\\ &=& ab + 2(a+b) + 4\\ &=& -3 + 2(\frac{3}{2}) + 4\\ &=& 4 \end{eqnarray} $$

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