Solve algebraically for all values of x

Which of the following circles have their centers in the third quadrant? check all that apply.

Find the center of the circle that can be circumscribed about efg with e(4,4) f(4,2) g(8,2)

Becca wants to mix fruit juice and soda to make a punch. she can buy fruit juice for $3 a gallon and soda for $4 a gallon. if she wants to make 28 gallons of punch at a cost of $3.25 a gallon, how many gallons of fruit juice and how many gallons of soda should she buy?