Question 232225
y= -x2 + 6x - 5.5
{{{ graph( 300, 200, -6, 5, -10, 10, -x^2 +6x -5.5) }}} (graph 300x200 pixels, x from -6 to 5, y from -10 to 10, -x^2 +6x -5.5). 
y=-3^3+6*3-5,5
y=-9+18-5,5
y=18-14.5
y=3.5
Vertex=(3,3.5)