Find the coordinates of the vertex for the following parabol

Find the coordinates of the vertex for the following parabola.

y=14x25x5

I need to know the steps.

The given Parabola is y=14x^25x5

For vertex of parabola

dy/dx=0

Or, 28x-5=0

Or, x=5/28

and y=14x^25x5=14(5/28)^2 -5 (5/28)-5= -305/56

so the vertx is (5/28, -305/56)