f(x)=3-4x
g(x)=3+4x
show that f^-1(x)+g^-1(x)=0, for all the values of x.
The first one f(x) = y = 3-4x solve for 'x'
y-3 = -4x
3-y = 4x
(3-y)/4 = x now switch the x's and y's
f^-1 (x) = (3-x)/4
The second one y=3+4x
(y-3)/4 = x
f^-1 (x) = (x-3)/4
Now add the two f^-1 (x) in red (3-x)/4 + (x-3)/4 = (x-x +3-3)/4 = 0
The first one f(x) = y = 3-4x solve for 'x'
y-3 = -4x
3-y = 4x
(3-y)/4 = x now switch the x's and y's
f^-1 (x) = (3-x)/4
The second one y=3+4x
(y-3)/4 = x
f^-1 (x) = (x-3)/4
Now add the two f^-1 (x) in red (3-x)/4 + (x-3)/4 = (x-x +3-3)/4 = 0