Let's solve the puzzle step by step, evaluating each function as required.

1. Evaluate $f(-2)$: The function is given as $f(x) = x^3 - 2x$.

   $f(-2) = (-2)^3 - 2(-2) = -8 + 4 = -4$

2. Evaluate $g(-10)$: The function is given as $g(x) = \frac{3x}{2}$.

   $g(-10) = \frac{3(-10)}{2} = \frac{-30}{2} = -15$

3. Evaluate $h(-1)$: The function is given as $h(x) = 2x^2 + x$.

   $h(-1) = 2(-1)^2 + (-1) = 2(1) - 1 = 2 - 1 = 1$

4. Evaluate $f(3)$: The function is again $f(x) = x^3 - 2x$.

   $f(3) = 3^3 - 2(3) = 27 - 6 = 21$

Final values:

• $f(-2) = -4$
• $g(-10) = -15$
• $h(-1) = 1$
• $f(3) = 21$

The corresponding answers from the choices are:

• $f(-2) = -4$ → C
• $g(-10) = -15$ → H
• $h(-1) = 1$ → G
• $f(3) = 21$ → D

So, the 4-letter code is: CHGD.

Would you like further details or have any questions?

Here are 5 related questions to practice:

1. Evaluate $f(0)$.
2. Evaluate $g(5)$.
3. Find $h(2)$.
4. What is the value of $f(4)$?
5. Solve for $x$ if $f(x) = 0$.

Tip: Always check if functions can be simplified before solving for a specific value.