In order to find the vertex, you first need to find the axis of symmetry- the formula is (A.O.S) x = \frac{-b}{2a}
So you would multiply 12 by -1 and get -12, then multiply 2 by 2 (a) and you should get 4.
In order to get the A.O.S, divide -12 by 4 = -3
Finally, plug in x (or the A.O.S)
Your equations should now look like this;
y = 2 (-3) ^2 + 12 (-3) +26
Solve each part separately and then add it up:
-3^2 = 9 * 2 = 18
12 * -3 = -36
and just 26
18 - 36 + 36
Vertex (or y) = 18
