To find the vertex of the parabola given by the equation \( y = -3x^2 + 36x - 120 \), we can use the formula for the x-coordinate of the vertex of a parabola in the form \( y = ax^2 + bx + c \), which is given by:
\[ x = -\frac{b}{2a} \]
Here, \( a = -3 \) and \( b = 36 \).
Plugging in the values:
\[ x = -\frac{36}{2(-3)} = -\frac{36}{-6} = 6 \]
Now that we have the x-coordinate, we can find the y-coordinate by substituting \( x = 6 \) back into the original equation:
\[ y = -3(6)^2 + 36(6) - 120 \] \[ y = -3(36) + 216 - 120 \] \[ y = -108 + 216 - 120 \] \[ y = 108 - 120 = -12 \]
Thus, the coordinates of the vertex of the parabola are:
\[ \boxed{(6, -12)} \]