Question 126845
f(x)=x^2-16x+66
{{{ graph( 300, 200, -6, 15, -10, 10, x^2 -16x +66) }}} (graph 300x200 pixels, x from -6 to 15, y from -10 to 10, x^2 -16x +66). 
The function obviously has a minimum.