Complete Square 039Eed
1. **State the problem:** Express the quadratic polynomial $2x^2 + 8x + 6$ in complete square form.
2. **Recall the formula:** A quadratic $ax^2 + bx + c$ can be written as $a(x - h)^2 + k$ where $(h, k)$ is the vertex.
3. **Factor out the coefficient of $x^2$ from the first two terms:**
$$2x^2 + 8x + 6 = 2(x^2 + 4x) + 6$$
4. **Complete the square inside the parentheses:**
Take half of the coefficient of $x$, which is 4, half is 2, square it to get $2^2 = 4$.
Add and subtract 4 inside the parentheses:
$$2(x^2 + 4x + 4 - 4) + 6 = 2((x + 2)^2 - 4) + 6$$
5. **Simplify:**
$$2(x + 2)^2 - 8 + 6 = 2(x + 2)^2 - 2$$
6. **Final answer:**
The quadratic in complete square form is
$$2(x + 2)^2 - 2$$
This matches the vertex at $(-2, -2)$ as given.