To determine which of the given quadratic equations is not solvable by grouping, we can check if they can be factored easily into binomials.
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2x² - 2x - 10 = 0
- First, factor out the common factor of 2: \[ 2(x² - x - 5) = 0 \]
- The quadratic \( x² - x - 5 \) does not factor nicely into integers.
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x² - 2x + 1 = 0
- This can be factored as: \[ (x - 1)(x - 1) = 0 \]
- It has a double root and is easily factored.
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x² - 12x + 35 = 0
- This can be factored as: \[ (x - 5)(x - 7) = 0 \]
- It factors nicely into integers.
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2x² + 14x + 12 = 0
- We can factor out 2: \[ 2(x² + 7x + 6) = 0 \]
- The quadratic \( x² + 7x + 6 \) can be factored as: \[ (x + 1)(x + 6) = 0 \]
From the analysis, the quadratic equation that is not easily factored into integers (and thus not solvable by grouping) is:
2x² - 2x - 10 = 0.