Problem
Let $f(x)=4 x-1, h(x)=x-1$ Find $(f \circ f)(6)$
Solution
Step 1 ：Define the function \(f(x)=4x-1\).
Step 2 ：Evaluate \(f(6)\) to get \(f(6)=23\).
Step 3 ：Substitute \(f(6)\) back into the function to get \(f(f(6))=f(23)\).
Step 4 ：Evaluate \(f(23)\) to get \(f(23)=91\).
Step 5 ：So, \((f \circ f)(6) = \boxed{91}\).
