Question: Solve the following quadratic function by completing the square.
y = x² − 6x − 5
x = [?] ± √[ ]
1. **State the problem:** We need to solve the quadratic equation $$y = x^2 - 6x - 5$$ by completing the square.
2. **Recall the formula and rule:** To complete the square for an equation of the form $$x^2 + bx + c$$, we add and subtract $$\left(\frac{b}{2}\right)^2$$ inside the equation to form a perfect square trinomial.
3. **Rewrite the equation:**
$$y = x^2 - 6x - 5$$
4. **Complete the square:**
Take half of the coefficient of $$x$$, which is $$-6$$, so half is $$\frac{-6}{2} = -3$$.
Square it: $$(-3)^2 = 9$$.
Add and subtract 9 inside the equation:
$$y = (x^2 - 6x + 9) - 9 - 5$$
5. **Factor the perfect square trinomial:**
$$y = (x - 3)^2 - 14$$
6. **Set $$y = 0$$ to find the roots:**
$$0 = (x - 3)^2 - 14$$
7. **Isolate the square term:**
$$ (x - 3)^2 = 14 $$
8. **Take the square root of both sides:**
$$ x - 3 = \pm \sqrt{14} $$
9. **Solve for $$x$$:**
$$ x = 3 \pm \sqrt{14} $$
**Final answer:**
$$ x = 3 \pm \sqrt{14} $$
This matches the form $$x = [?] \pm \sqrt{[ ]}$$ with $$3$$ in place of $$[?]$$ and $$14$$ in place of $$[ ]$$.