MATHEMATICS · Multi-part · AP · AP Precalculus · Polynomial and Rational Functions · Polynomial and Rational Functions
Problem
Let f(x)=x2−4x−212x+5.
(i) Solve the equation x2−4x−21=0 and list all its real roots.
(ii) Using the roots obtained in part (i), determine the domain of f(x).
(iii) Verify explicitly that f(x) is undefined at each excluded value found in part (ii).