In the circumference formula given d is the diameter which is 2 times r ( r is the radius)
R is given as 6 feet, diameter = 2 x 6 = 12 feet.
Circumference = 12 feet x 3.14 = 37.68 feet
Input 3y+11 for x
2(3y+11)-3y=16
6y+22-3y=16
3y= -6
Divide by 3 to isolate y
y=-2
Now for x....
x=3(-2)+11
=-6+11
=5
x=5
Coordinates (5,-2)