1. **State the problem:** We need to find the values of $m$ such that the line $y = mx - 6$ is tangent to the curve $y = x^2 - 4x + 3$. Also, find the coordinates of the tangent points.
2. **Set the line equal to the curve:** Since the line is tangent, it touches the curve at exactly one point. So, set
$$mx - 6 = x^2 - 4x + 3$$
3. **Rearrange to form a quadratic equation:**
$$x^2 - 4x + 3 - mx + 6 = 0$$
$$x^2 - (4 + m)x + 9 = 0$$
4. **Condition for tangency:** A quadratic has exactly one solution when its discriminant $D = 0$. The discriminant is
$$D = b^2 - 4ac$$
Here, $a=1$, $b=-(4+m)$, $c=9$.
5. **Calculate discriminant:**
$$D = (-(4+m))^2 - 4(1)(9) = (4+m)^2 - 36$$
6. **Set discriminant to zero:**
$$ (4+m)^2 - 36 = 0 $$
$$ (4+m)^2 = 36 $$
$$ 4+m = \pm 6 $$
7. **Solve for $m$:**
- If $4 + m = 6$, then $m = 2$
- If $4 + m = -6$, then $m = -10$
8. **Find tangent points:** Substitute $m$ back into the quadratic to find $x$.
For $m=2$:
$$x^2 - (4+2)x + 9 = x^2 - 6x + 9 = 0$$
$$x^2 - 6x + 9 = 0$$
Discriminant is zero, so one root:
$$x = \frac{6}{2} = 3$$
Find $y$ on the line:
$$y = 2(3) - 6 = 6 - 6 = 0$$
Tangent point: $(3, 0)$
For $m = -10$:
$$x^2 - (4 - 10)x + 9 = x^2 + 6x + 9 = 0$$
$$x^2 + 6x + 9 = 0$$
Discriminant zero, root:
$$x = \frac{-6}{2} = -3$$
Find $y$ on the line:
$$y = -10(-3) - 6 = 30 - 6 = 24$$
Tangent point: $(-3, 24)$
**Final answer:**
- Possible values of $m$ are $2$ and $-10$.
- Corresponding tangent points are $(3, 0)$ and $(-3, 24)$ respectively.
Tangent Line 025Ff3
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