This parabola has a minimum (since the coefficient of x^2 is positive). To find the vertex of a quadratic equation ax^2 + bx + c =0, you calculate (-b/a) or in our case (-6/4) = -3/2. This is the value of x. Now to find the value of y, you just plug x by its value (-3/2) & you'll find y =(-25/2) so the coordinate of the vertex are (-3/2 , -25/2).
Hope this is clear
