To determine which quadratic equation is not solvable by grouping, we can look at the ability to factor each equation.
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2x² + 14x + 12 = 0
This can be factored: Factor out a 2 first:
\(2(x^2 + 7x + 6) = 0\)
Then \(x^2 + 7x + 6\) can be factored into \((x + 1)(x + 6)\), so this is solvable by grouping. -
2x² − 2x − 10 = 0
Factor out a 2:
\(2(x^2 - x - 5) = 0\)
The expression \(x^2 - x - 5\) does not factor nicely into rational numbers, thus it's not directly solvable by grouping. -
x² − 12x + 35 = 0
This factors into \((x - 5)(x - 7) = 0\). So this is solvable by grouping. -
x² − 2x + 1 = 0
This can be factored into \((x - 1)(x - 1) = (x - 1)^2 = 0\). So this is also solvable by grouping.
Based on this analysis, the equation that is not solvable by grouping is:
2x² − 2x − 10 = 0.