X^2+15^2=21^2
Help me please how do I figure out X after getting the totals of b and c?

Given the choice between receiving $1.000.000 in one month or a single penny-doubled everyday for the period of one month; which option would you choice? show your work to support your answer. (assume that 1 month=30 days)

Solve the system of equations. y= 2x y= x^2 - 15

Ten times the square of a non-zero number is eqaul to ninety times the number