1. **State the problem:** We need to find the sign diagram for the quadratic function $$y = -x^2 + 4x - 3$$.
2. **Recall the formula and rules:** The sign diagram shows where the function is positive, negative, or zero. To find this, we first find the roots by solving $$-x^2 + 4x - 3 = 0$$.
3. **Solve the quadratic equation:** Multiply both sides by -1 to simplify:
$$x^2 - 4x + 3 = 0$$
Factor the quadratic:
$$ (x - 3)(x - 1) = 0 $$
So, the roots are $$x = 1$$ and $$x = 3$$.
4. **Determine the sign intervals:** The roots divide the number line into three intervals: $$(-\infty, 1)$$, $$(1, 3)$$, and $$(3, \infty)$$.
5. **Test each interval:**
- For $$x < 1$$, pick $$x=0$$:
$$y = -(0)^2 + 4(0) - 3 = -3 < 0$$
- For $$1 < x < 3$$, pick $$x=2$$:
$$y = -(2)^2 + 4(2) - 3 = -4 + 8 - 3 = 1 > 0$$
- For $$x > 3$$, pick $$x=4$$:
$$y = -(4)^2 + 4(4) - 3 = -16 + 16 - 3 = -3 < 0$$
6. **Conclusion:** The function is negative on $$(-\infty, 1)$$, positive on $$(1, 3)$$, and negative on $$(3, \infty)$$.
**Final answer:**
- Sign diagram intervals:
- $$y < 0$$ for $$x < 1$$
- $$y > 0$$ for $$1 < x < 3$$
- $$y < 0$$ for $$x > 3$$
- Zeros at $$x = 1$$ and $$x = 3$$ where $$y = 0$$.
Sign Diagram
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