At what point, the slope of curve y = -x3 + 3x2 + 9x - 27 is maximum ? Also find the maximum slope.

At what point the slope of curve y = -x3 + 3x2 + 9x - 27 is maximum ? Also find the maximum slope.

We have, y = -x,3, + 3x,2, + 9x - 27,∴ dy/dx = -3x,2 ,+ 6x + 9 = slope of tangent to the curve