What is the vertex of the graph of y = x^2 - 19x + 74?

-b/2a will be the 'x' value a = 1 b = -19

use this value in the equation to calculate the 'y' value of the vertex .....

Anther way you can solve this is by completing the square...

then you can use the general formula ...

y = (x-h)^2 + (y-k)^2 where (h,k) is the vertex,

I am sure you meant y = a(x-h)^2 + k where h,k is the vertex

Sorry I was thinking of the Formula for the graph of a circle.