Question: User: $\left(3y+3\right)$ $^2$
1. **State the problem:** Simplify the expression $$\left(3y+3\right)^2$$.
2. **Recall the formula:** The square of a binomial is given by $$\left(a+b\right)^2 = a^2 + 2ab + b^2$$.
3. **Identify terms:** Here, $a = 3y$ and $b = 3$.
4. **Apply the formula:**
$$\left(3y+3\right)^2 = (3y)^2 + 2 \times 3y \times 3 + 3^2$$
5. **Calculate each term:**
$$= 9y^2 + 18y + 9$$
6. **Final answer:**
$$9y^2 + 18y + 9$$