Find \(f^{-1}(x)\)
📝 Question
Let:
\[ f(x)=4-(x-7)^3 \]
Find \(f^{-1}(x)\).
✅ Solution
🔹 Step 1: Let
\[ y=4-(x-7)^3 \] —
🔹 Step 2: Solve for \(x\)
\[ (x-7)^3=4-y \]
Take cube root:
:contentReference[oaicite:0]{index=0}\[ x=7+\sqrt[3]{4-y} \] —
🔹 Step 3: Write inverse
Interchange \(x\) and \(y\):
\[ f^{-1}(x)=7+\sqrt[3]{4-x} \] —
🎯 Final Answer
\[ \boxed{f^{-1}(x)=7+\sqrt[3]{4-x}} \]
🚀 Exam Shortcut
- Shift and cube structure
- Undo operations in reverse order
- Cube → cube root, subtract → add