To determine if \( x = -3 \) is a solution to the quadratic equation \(-3x^2 - 9x = 0\), we need to substitute \( x = -3 \) into the equation and see if it holds true.
Starting with the equation: \[ -3x^2 - 9x = 0 \]
Substituting \( x = -3 \): \[ -3(-3)^2 - 9(-3) = 0 \]
Calculating \((-3)^2\): \[ -3(9) - 9(-3) = 0 \]
Now simplifying: \[ -27 + 27 = 0 \]
This simplifies to: \[ 0 = 0 \]
Since this statement is true, it demonstrates that \( x = -3 \) is indeed a solution to the equation \(-3x^2 - 9x = 0\).
Therefore, the correct reasoning is that substituting \( -3 \) into the equation yields a true statement, confirming that \( x = -3 \) is a solution.