If f(x)=−x^2−8x+7, and g(x)=x−1, what does (g−f)(x) equal?

(g−f)(x)=−x^2−7x+6
(g−f)(x)=x^2+9x−8
(g−f)(x)=−x^2−9x+8
(g−f)(x)=−8x+8