WILL GIVE BRAINLIEST, ANSWER ONE OR BOTH I DONT CARE JUST PLSSS HELP

15 point ! ~ see if you know the answer to both you!

When the ball has traveled a distance of

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.