To determine which of the given quadratic equations is not solvable by grouping, we'll analyze each equation.
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\(x^2 - 12x + 35 = 0\):
- Factors: \( (x - 5)(x - 7) = 0 \)
- This can be solved by finding the roots.
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\(x^2 - 2x + 1 = 0\):
- Factors: \( (x - 1)(x - 1) = 0 \) or \( (x - 1)^2 = 0 \)
- This can also be solved by finding the roots (perfect square).
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\(2x^2 + 14x + 12 = 0\):
- We can factor out a 2: \( 2(x^2 + 7x + 6) = 0 \)
- Then, it factors as \( 2(x + 1)(x + 6) = 0 \)
- This can be solved by finding the roots.
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\(2x^2 - 2x - 10 = 0\):
- First, divide the entire equation by 2: \( x^2 - x - 5 = 0 \)
- This quadratic does not factor nicely and does not lend itself to grouping.
Among the given options, the equation \(2x^2 - 2x - 10 = 0\) (or simplified \(x^2 - x - 5 = 0\)) is the one not easily solvable by grouping, as its factors are not integers.
So, the answer is \(2x^2 - 2x - 10 = 0\).