For 50 points
for the function f(x)=-4 sqrt x-1 find the inverse function
a) f^-1(x)=-(x+1)^2/16, x< _-1
b) f^-1(x)=(x+1)^2/16 , x> _-1
c) f^-1(x)=(x+1)^2/16
d)f^-1(x)=(x+1)^2/16, x< _-1
only answer if you really know, . im really struggling with my class and need some if someone could walk me through this that would mean the world to me.