To find the circumference of a circle that lists only as a diameter, you would do pi*d so lets say the diameter is 6, you would do pi*6 which would end up giving you 18.84. I hope this helps a bit! (:
Use elimination.
-x = -6
X = 6
-4 (6) + 4y = 12
Y = 9
(X,y)
(6,9) is the solution
The last one because it can be traced like Jerome gets these cards from this place but others from a different place