Question: Consider the quadratic function $y = 3x^2 + 30x + 65$. Rewrite the function in vertex format.
1. **State the problem:** We need to rewrite the quadratic function $y = 3x^2 + 30x + 65$ in vertex form.
2. **Recall the vertex form:** The vertex form of a quadratic function is $$y = a(x - h)^2 + k$$ where $(h, k)$ is the vertex.
3. **Complete the square:**
Start with the original function:
$$y = 3x^2 + 30x + 65$$
Factor out the coefficient of $x^2$ from the first two terms:
$$y = 3(x^2 + 10x) + 65$$
To complete the square inside the parentheses, take half of the coefficient of $x$, which is $10$, half is $5$, and square it: $5^2 = 25$.
Add and subtract $25$ inside the parentheses:
$$y = 3(x^2 + 10x + 25 - 25) + 65$$
Group the perfect square trinomial and simplify:
$$y = 3((x + 5)^2 - 25) + 65$$
Distribute the $3$:
$$y = 3(x + 5)^2 - 3 \times 25 + 65$$
$$y = 3(x + 5)^2 - 75 + 65$$
Simplify the constants:
$$y = 3(x + 5)^2 - 10$$
4. **Interpretation:** The vertex form is $$y = 3(x + 5)^2 - 10$$ with vertex at $(-5, -10)$.
5. **Answer:** The correct vertex form is $y = 3(x + 5)^2 - 10$.
This corresponds to the option: $y = 3(x + 5)^2 - 10$.