F: x - -x+1, x e={-1, 0, 1, 2}
g: x - 5, xe{ -1, 0, 1 ,2}
h: x - f(x) x g(x)

constructs the cartesian graph of the function h

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.