Guess my favorite color ya

Joe has some money in his bank account he deposits 45$ write an expression that represents the amount of money in joe's account

The value of the expression 16-^3/4 8 1/8 -6 6 1/40 1/64

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.