The cooking club made some pies to sell at a basketball game to raise money for the new math book. the cafeteria contributed three pies to the sale. each pie was then cut into seven pieces and sold. there were a total of 91 pieces to sell. how many pies did the club make?

Well, if the cafeteria contributed 3 pies and they were cut into 7 pieces, there would be 21 pieces of pie.
If you subtract that from 91 pieces they sold it would equal to 70 pieces. You then divide that into 7 pieces (to make a whole) and you get 10.
So the cooking club made 10 pies

X^2 - 4x +(4/2^2) + y^2 + 8y + (8/2^2) = -4 + (4/2^2) + (8/2^2)(x + 2)^2 + (y + 4)^2 = -4 + 4 + 16your center is (-2, -4) and the radius is the sqrt of -4 + 4 + 16 which is 4