To solve the equation \(3x^2 - 20 = 7\) by factoring, we first rearrange the equation to set it to zero:
\[ 3x^2 - 20 - 7 = 0 \]
This simplifies to:
\[ 3x^2 - 27 = 0 \]
Now, we can factor out a common factor from the left side:
\[ 3(x^2 - 9) = 0 \]
Next, we recognize that \(x^2 - 9\) is a difference of squares, which can be factored as:
\[ 3(x - 3)(x + 3) = 0 \]
Now, we set each factor equal to zero:
- \(x - 3 = 0 \Rightarrow x = 3\)
- \(x + 3 = 0 \Rightarrow x = -3\)
So the solutions to the equation \(3x^2 - 20 = 7\) are:
\[ x = 3 \quad \text{and} \quad x = -3 \]
Thus, the correct solutions are \(x = -3\) and \(x = 3\).