Tangent Line Bee2C9
1. **State the problem:** We are given a function $g(x) = x f(x)$, with $f(3) = 4$ and $f'(3) = -2$. We need to find the equation of the tangent line to the graph of $g$ at $x = 3$.
2. **Recall the formula for the tangent line:** The tangent line to $g$ at $x = a$ is given by
$$y = g(a) + g'(a)(x - a)$$
where $g'(a)$ is the derivative of $g$ evaluated at $x = a$.
3. **Find $g'(x)$ using the product rule:** Since $g(x) = x f(x)$,
$$g'(x) = f(x) + x f'(x)$$
(Product rule: derivative of first times second plus first times derivative of second.)
4. **Evaluate $g(3)$:**
$$g(3) = 3 \times f(3) = 3 \times 4 = 12$$
5. **Evaluate $g'(3)$:**
$$g'(3) = f(3) + 3 \times f'(3) = 4 + 3 \times (-2) = 4 - 6 = -2$$
6. **Write the equation of the tangent line:**
$$y = g(3) + g'(3)(x - 3) = 12 - 2(x - 3) = 12 - 2x + 6 = 18 - 2x$$
**Final answer:**
$$y = 18 - 2x$$