What is the vertex of x^2+10x=-17

Writing this as a function:  y  =  x² + 10x + 17

Now:                         y - 17  = x² + 10x

Completing the square:

                       y - 17 + 25  =  x² + 10x + 25

                                y + 8  =  (x + 5)²

The vertex  occurs at (-5, -8)