To solve the equation \(3x^2 - 20 = 7\) by factoring, we first need to rearrange the equation:
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Move all terms to one side: \[ 3x^2 - 20 - 7 = 0 \] \[ 3x^2 - 27 = 0 \]
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Factor out the common factor: \[ 3(x^2 - 9) = 0 \]
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Recognize that \(x^2 - 9\) is a difference of squares: \[ x^2 - 9 = (x - 3)(x + 3) \]
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Thus, we have: \[ 3(x - 3)(x + 3) = 0 \]
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Set each factor equal to zero: \[ 3 = 0 \quad \text{(not applicable)} \] \[ x - 3 = 0 \quad \Rightarrow \quad x = 3 \] \[ x + 3 = 0 \quad \Rightarrow \quad x = -3 \]
So, the solutions to the equation \(3x^2 - 20 = 7\) are \(x = 3\) and \(x = -3\).
Thus, the correct solutions are: \[ \boxed{3 \text{ and } -3} \]