Write x^2+2rx+7 in the form a(x+b)^2+c, where b and c are given in terms of r.

Sasha delivers newspapers to subscribers that live within a 4 block radius of her house. sasha's house is located at point (0, -1). points a, b, c, d, and e represent the houses of some of the subscribers to the newspaper. to which houses does sasha deliver newspapers?