[2] c) $f^{-1}(x)=\frac{1}{4} x-10$

Step 1 ：Switch the roles of x and y in the function: \(x = \frac{1}{4} y - 10\)

Step 2 ：Solve for y: \(y = 4(x + 10)\)

Step 3 ：Write the inverse function: \(f^{-1}(x) = 4(x + 10)\)

Step 4 ：Evaluate the inverse function at 2: \(f^{-1}(2) = 4(2 + 10)\)

Step 5 ：\(f^{-1}(2) = 4(12)\)

Step 6 ：Final Answer: \(\boxed{48}\)