#### To determine

**To find**: The inverse of the given function.

#### Answer

**Answer:f-1x=(5-x)/4**.

#### Explanation

fx=5-4x.

**Step 1**: Substitute y=f(x), i.e.,y=5-4x. By solving this equation for the value of x, we get x=(5-y)/4.

**Step 2**: Interchange the positions of x and y, we get y=(5-x)/4.

**Conclusion:** Therefore,f-1x=(5-x)/4.