Question 1164097
Perimeter is sum of 
3x-2y
x+6y
4x-6y, multiplying by 2
8x-2y
the sides are equal
so 3x-2y=x+6y
2x=8y
x=4y

check with the third
x+6y=4x-6y
3x=12y
x=4y

Therefore 8x-2y above is 32y-2y=30y
or y=(1/4)x
8x-2y=30x/4 or 7.5 x
Both those express the perimeter.