Help me find the vertex

Hello, I need to graph a Parabola with this equation.
y=3m^2+11m+4

I have the two points already plotted on the graph. I just need the vertex.
I keep getting something like -1.8, 13.4
That can't be right, because it's supposed to look like it's smiling, not frowning.

Thanks

if you have 2 points on the same y coordinate
so for example (not an example from this equation):
0,5 and 10, 5

that means for an input of 0 and 10 for m
your equation is equal to 5
the vertex is always halfway between two identical y coordinates. Meaning 10 + 0 = 10 div 2 = 5

sub in 5 and you get a y input that is greatest.

complete the square. factor out a 3.

y=3(m^2+(11/3)m+4/3)
b=11/3
b/2=11/6
(b/2)^2=121/36
y=3((m+11/6)^2+4/3-121/36))
y=3((m+11/6)^2-73/36)
y=3(m+11/6)^2-73/12
vertex=(-11/6,-73/12)

you can use following url