Answer
y=7/2 +3/2x
Step-by-step explanation:
Subtract over 3x then divide -2y by 7 and -3x, remember to watch your signs.
the answer would come out to be

Why?
We can find the perimeter of any triangle adding the length of its sides. Since we are given 3 points, we need to calculate the length of the three sides of the triangle, and then add them to know the perimeter of the triangle.
Let be the points:
A(-3,-1)
B(-1,2)
C(6,1)
<h3>
- Distances</h3>
From A to B:

From A to C:

From B to C:

Now, calculating the perimeter, we have:

Have a nice day!