1. **State the problem:** We need to find the coordinates of the vertices of the triangle formed by the intersection of the three lines:
$$y = x + 1$$
$$y = 4 - 2x$$
$$y = -x - 5$$
2. **Method:** The vertices of the triangle are the points where each pair of lines intersect. We will find these points algebraically by solving the systems of equations pairwise.
3. **Find intersection of** $y = x + 1$ **and** $y = 4 - 2x$:
Set the right sides equal:
$$x + 1 = 4 - 2x$$
Add $2x$ to both sides:
$$x + 2x + 1 = 4$$
$$3x + 1 = 4$$
Subtract 1 from both sides:
$$3x = 3$$
Divide both sides by 3:
$$\cancel{3}x = \cancel{3}1$$
$$x = 1$$
Substitute $x=1$ into $y = x + 1$:
$$y = 1 + 1 = 2$$
So, the first vertex is $(1, 2)$.
4. **Find intersection of** $y = 4 - 2x$ **and** $y = -x - 5$:
Set equal:
$$4 - 2x = -x - 5$$
Add $2x$ to both sides:
$$4 = -x + 2x - 5$$
$$4 = x - 5$$
Add 5 to both sides:
$$4 + 5 = x$$
$$9 = x$$
Substitute $x=9$ into $y = 4 - 2x$:
$$y = 4 - 2(9) = 4 - 18 = -14$$
So, the second vertex is $(9, -14)$.
5. **Find intersection of** $y = x + 1$ **and** $y = -x - 5$:
Set equal:
$$x + 1 = -x - 5$$
Add $x$ to both sides:
$$x + x + 1 = -5$$
$$2x + 1 = -5$$
Subtract 1 from both sides:
$$2x = -6$$
Divide both sides by 2:
$$\cancel{2}x = \cancel{2}(-3)$$
$$x = -3$$
Substitute $x = -3$ into $y = x + 1$:
$$y = -3 + 1 = -2$$
So, the third vertex is $(-3, -2)$.
6. **Final answer:** The vertices of the triangle are:
$$(1, 2), (9, -14), (-3, -2)$$
7. **Graphical solution:** Plotting these three lines on a graph will show that they intersect at these points, forming a triangle with the vertices found algebraically.
This completes the solution.
Triangle Vertices B4Cabe
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