10/2=5 because 2x___=10 pls help

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.

Given δjkl : δxyz, find x. a)10 b)12 c)16 d)20

Is the ordered pair (-10, 7) a solution to the equation y = 17 – x? yes or no