You have the following information:
- Allie owes her parents $43
- Lasth month She owed them 3 times as much, that is she owed
3 x $43 = $129
You can write the previous situation with negative integers, as follow:
you consider the debt as a negative quantity:
Allie owes her parents $43 : - 43
She owed $129 = -129
If she owed $129 last month, this means she payed $129 - $43 = $86 to her parents this month. Then, she payed $83 = + 83
Summarizing, you have:
- 129 + 83 = - 43