(a) (t - u)^2 + 2u(t - u) = t^2 - u^2
After converting the original quadratic equation (ax^2 + bx + c = 0) into
x^2 + (b/a)x = -(c/a)introduce the auxilliary variables t and u, where x = t - u. Then, using (a), find t and u (and ultimately x) in terms of a, b, and c.