**Solution:**

Given equations are x – y + 1 = 0 and 3x + 2y – 12 = 0.

Let’s consider the equation x – y + 1 = 0.

y = x + 1

x | 0 | 1 | 2 |

y | 1 | 2 | 3 |

Now, consider the second equation 3x + 2y – 12 = 0

2y = 12 – 3x

y = (12 – 3x)/2

x | 0 | 2 | 4 |

y | 6 | 3 | 0 |

Hence, the graphical representation of these equations is as follows.

From the figure, it can be seen that these lines are intersecting each other at points (2, 3) and the x-axis at (−1, 0) and (4, 0).

Therefore, the vertices of the triangle are (2, 3), (−1, 0), and (4, 0).