To determine which of the given quadratic equations is not solvable by factoring, we can check the discriminants of each one or attempt to factor them directly.
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2x² + 14x + 12 = 0
We can factor out a 2: \( 2(x² + 7x + 6) = 0 \)
Now, factor the quadratic: \( x² + 7x + 6 = (x + 1)(x + 6) \)
Thus, it is factorable.
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x² - 12x + 35 = 0
This factors directly as: \( (x - 5)(x - 7) = 0 \)
So, it is factorable.
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x² - 2x + 1 = 0
This factors to: \( (x - 1)(x - 1) = (x - 1)² = 0 \)
Thus, it is also factorable.
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2x² - 2x - 10 = 0
We can first factor out a 2: \( 2(x² - x - 5) = 0 \)
Now we check if \( x² - x - 5 \) can be factored. The discriminant (\(b² - 4ac\)) is: \[ (-1)² - 4(1)(-5) = 1 + 20 = 21 \] The discriminant is positive, but since it does not yield a perfect square, it is not factorable over the integers.
Therefore, the equation that is not solvable by factoring is 2x² - 2x - 10 = 0.