1. We found numbers h and k such that, for every real number
x, ax^2 + bx + c = a(x − h)^2 + k as long as a, b and c are real numbers and a≠0.

(a) What are those numbers h and k in terms of a, b and c?

(b) Now, if a > 0, use the fact that t^2 ≥ 0 for every real number t to conclude ax^2+ bx + c ≥ k for every real number x.