Find the solution(s) of the system of equations. x2 + y2 = 18
y= x + 6

A) (3, 3) and (-3, -3)
B) (-3, 3) and (3,9)
C) (-3,3)
D) (3,9)

Parabolas y=−2x^2 and y=2x^2 +k intersect at points a and b that are in the third and the fourth quadrants respectively. find k if length of the segment ab is 5.