1. **Stating the problem:**
We need to find the shape of the region defined by the system of inequalities:
$$4x + y \geq 8$$
$$3x + 4y \leq 24$$
$$x + 6y \geq 12$$
2. **Understanding the problem:**
Each inequality represents a half-plane bounded by a line. The solution region is the intersection of these half-planes.
3. **Find the boundary lines by converting inequalities to equalities:**
- Line 1: $$4x + y = 8$$
- Line 2: $$3x + 4y = 24$$
- Line 3: $$x + 6y = 12$$
4. **Find the intersection points of these lines to determine vertices of the polygon:**
- Intersection of Line 1 and Line 2:
$$\begin{cases}4x + y = 8 \\ 3x + 4y = 24\end{cases}$$
Multiply first equation by 4:
$$16x + 4y = 32$$
Subtract second equation:
$$16x + 4y - (3x + 4y) = 32 - 24$$
$$13x = 8$$
$$x = \frac{8}{13}$$
Substitute back:
$$4 \times \frac{8}{13} + y = 8$$
$$\frac{32}{13} + y = 8$$
$$y = 8 - \frac{32}{13} = \frac{104}{13} - \frac{32}{13} = \frac{72}{13}$$
- Intersection of Line 2 and Line 3:
$$\begin{cases}3x + 4y = 24 \\ x + 6y = 12\end{cases}$$
Multiply second equation by 3:
$$3x + 18y = 36$$
Subtract first equation:
$$3x + 18y - (3x + 4y) = 36 - 24$$
$$14y = 12$$
$$y = \frac{12}{14} = \frac{6}{7}$$
Substitute back:
$$x + 6 \times \frac{6}{7} = 12$$
$$x + \frac{36}{7} = 12$$
$$x = 12 - \frac{36}{7} = \frac{84}{7} - \frac{36}{7} = \frac{48}{7}$$
- Intersection of Line 1 and Line 3:
$$\begin{cases}4x + y = 8 \\ x + 6y = 12\end{cases}$$
Multiply second equation by 4:
$$4x + 24y = 48$$
Subtract first equation:
$$4x + 24y - (4x + y) = 48 - 8$$
$$23y = 40$$
$$y = \frac{40}{23}$$
Substitute back:
$$x + 6 \times \frac{40}{23} = 12$$
$$x + \frac{240}{23} = 12$$
$$x = 12 - \frac{240}{23} = \frac{276}{23} - \frac{240}{23} = \frac{36}{23}$$
5. **Vertices of the polygon are:**
$$\left(\frac{8}{13}, \frac{72}{13}\right), \left(\frac{48}{7}, \frac{6}{7}\right), \left(\frac{36}{23}, \frac{40}{23}\right)$$
6. **Conclusion:**
Since there are three vertices, the region is a triangle.
7. **Check the type of triangle:**
Calculate slopes of sides:
- Between $$\left(\frac{8}{13}, \frac{72}{13}\right)$$ and $$\left(\frac{48}{7}, \frac{6}{7}\right)$$:
$$m_1 = \frac{\frac{6}{7} - \frac{72}{13}}{\frac{48}{7} - \frac{8}{13}} = \frac{\frac{78}{91} - \frac{504}{91}}{\frac{336}{91} - \frac{56}{91}} = \frac{-\frac{426}{91}}{\frac{280}{91}} = -\frac{426}{280} = -\frac{213}{140}$$
- Between $$\left(\frac{48}{7}, \frac{6}{7}\right)$$ and $$\left(\frac{36}{23}, \frac{40}{23}\right)$$:
$$m_2 = \frac{\frac{40}{23} - \frac{6}{7}}{\frac{36}{23} - \frac{48}{7}} = \frac{\frac{280}{161} - \frac{138}{161}}{\frac{252}{161} - \frac{1104}{161}} = \frac{\frac{142}{161}}{-\frac{852}{161}} = -\frac{142}{852} = -\frac{71}{426}$$
- Between $$\left(\frac{36}{23}, \frac{40}{23}\right)$$ and $$\left(\frac{8}{13}, \frac{72}{13}\right)$$:
$$m_3 = \frac{\frac{72}{13} - \frac{40}{23}}{\frac{8}{13} - \frac{36}{23}} = \frac{\frac{1272}{299} - \frac{520}{299}}{\frac{184}{299} - \frac{468}{299}} = \frac{\frac{752}{299}}{-\frac{284}{299}} = -\frac{752}{284} = -\frac{188}{71}$$
Check if any product of slopes equals -1 (perpendicular):
$$m_1 \times m_2 = -\frac{213}{140} \times -\frac{71}{426} = \frac{213 \times 71}{140 \times 426} \neq 1$$
$$m_2 \times m_3 = -\frac{71}{426} \times -\frac{188}{71} = \frac{188}{426} \neq 1$$
$$m_1 \times m_3 = -\frac{213}{140} \times -\frac{188}{71} = \frac{213 \times 188}{140 \times 71} \neq 1$$
No right angle, so the triangle is not right-angled.
**Final answer:** The region is a triangle but not a right triangle.
**Answer choice:** B. Segitiga sembarang
Region Shape 69C588
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