Given functions f and g, find (a) (f • g)(x) and its domain, and|(b) (g • f)(x) and its domain. \text { 76) } f(x)=\sqrt{x}, g(x)=x-1 \text { 78) } f(x)=x+2, g(x)=x^{\wedge} 4+x^{\wedge} 2-4