1. **State the problem:**
Rewrite the quadratic expression $2x^2 + 20x + 28$ in the form $a(x + b)^2 + c$, where $a$, $b$, and $c$ are integers.
2. **Formula and method:**
We use the method of completing the square for quadratics:
$$ax^2 + bx + c = a\left(x + \frac{b}{2a}\right)^2 + \left(c - a\left(\frac{b}{2a}\right)^2\right)$$
3. **Apply to the given quadratic:**
Given $2x^2 + 20x + 28$, here $a=2$, $b=20$, and $c=28$.
4. **Calculate $b/(2a)$:**
$$\frac{20}{2 \times 2} = \frac{20}{4} = 5$$
5. **Rewrite the quadratic:**
$$2x^2 + 20x + 28 = 2\left(x^2 + 10x\right) + 28$$
6. **Complete the square inside the parentheses:**
Add and subtract $5^2 = 25$ inside the parentheses:
$$2\left(x^2 + 10x + 25 - 25\right) + 28 = 2\left((x + 5)^2 - 25\right) + 28$$
7. **Distribute and simplify:**
$$2(x + 5)^2 - 2 \times 25 + 28 = 2(x + 5)^2 - 50 + 28 = 2(x + 5)^2 - 22$$
8. **Identify $a$, $b$, and $c$:**
$$a = 2, \quad b = 5, \quad c = -22$$
9. **Find the turning point:**
The turning point of $y = a(x + b)^2 + c$ is at $(-b, c)$.
So, the turning point is:
$$(-5, -22)$$
**Final answers:**
- $a = 2$
- $b = 5$
- $c = -22$
- Turning point coordinates: $(-5, -22)$
Quadratic Completion 601F38
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