Distributive property of 5 x (3+4)

Idon’t understand! use slope intercept form to solve: through: (2,5) slope= undefined

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.

Can someone tell me if this is perpendicular? !