For any real numbers a,b,c & d such that c & d are not both zero, the formula f(x)=(ax+b)/(cx+d) defines a real function.

a)find the domain & range of f.

b)Show that f is a one-to-one function if and only if ad-bc not=0

c)Show that if f is one-to-one, then f' is given by f^{-1}(x)=(dx-b)/(-cx+a) where c & a are both not zero

d) show that if f is one-to-one and a=-d then f^{-1}=f