The function is
.
Replace
with y.

Next switch x for y and y for x.
\
.
Next solve for y :
\
(Multiply each side by 4)
(Apply distributive property:
)
(Cancel common terms)
(Multiply:
)
(Add 16 to each side)
(Apply additive inverse property:
)
(Apply additive identity property:
)
The value of
.
Write in function notation, using
to represent the inverse of the function f.

"y " value substitute in above function,
.
The inverse function of
is
.