Evaluate \(f(-1)+f(2)+f(4)\)

🎥 Video Explanation

---

📝 Question

Let:

\[ f(x)= \begin{cases} 2x, & x>3 \\ x^2, & 1

Find \(f(-1)+f(2)+f(4)\).

---

✅ Solution

🔹 Step 1: Evaluate \(f(-1)\)

Since \(-1 \le 1\):

\[ f(-1)=3(-1)=-3 \] —

🔹 Step 2: Evaluate \(f(2)\)

Since \(1<2\le3\):

\[ f(2)=2^2=4 \] —

🔹 Step 3: Evaluate \(f(4)\)

Since \(4>3\):

\[ f(4)=2\times4=8 \] —

🔹 Step 4: Add Values

\[ f(-1)+f(2)+f(4)=-3+4+8=9 \] —

🔹 Final Answer

\[ \boxed{9} \]