Question 217858
y=6x^2+11x
{{{ graph( 300, 200, -6, 5, -10, 10, 6x^2 +11x) }}} (graph 300x200 pixels, x from -6 to 5, y from -10 to 10, 6x^2 +11x). 
Symmetry (x)=-b/2a=-11/2*6=-11/12 ans.
When x=-11/12 then:
y=6(-11/12)^2+11(-11/12)
y=6*.8403-121/12
y=5.042-10.083
y=-5.041 
The vertex is (-11/12,-5.041)