3. The trapezoid below contains a square and two right triangles. Find the perimeter of the trapezoid.

Explanation is in the file

cutt.ly/tz3yDpb

Using a graph tool

case 1) 
2x-y=-13
y=x+9
the solution is the point (-4,5)
see the attached figure N 1

case 2)
y=3x-7
y=2x-5
the solution is the point (2,-1)
see the attached figure N 2

case 3)
3x+2y=10
6x-y=10
the solution is the point (2,2)
see the attached figure N 3

case 4)
y=6
x=-5
the solution is the point (-5,6)
see the attached figure N 4

case 5)
4x-3y=5
3x+2y=-9
the solution is the point (-1,-3)
see the attached figure N 5

case 6)
x+y=7
x-y=-1
the solution is the point (3,4)
see the attached figure N 6

the answer in the attached figure