Y=x^2+14x+40 in vertex form by completing the square

Vertex form of a quadratic is:

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

y=x^2+14x+40

y-40=x^2+14x

y-40+49=x^2+14x+49

y+9=(x+7)^2

y=(x+7)^2-9