MathDB
Function

Source:

February 24, 2006
functionVietaalgebrapolynomialAMC

Problem Statement

Let ff be a function for which f(x3)=x2+x+1f\left(\frac x3\right)=x^2+x+1. Find the sum of all values of zz for which f(3z)=7f(3z)=7. (A) 13(B) 19(C) 0(D) 59(E) 53\text{(A)}\ -\frac13\qquad\text{(B)}\ -\frac19 \qquad\text{(C)}\ 0 \qquad\text{(D)}\ \frac59 \qquad\text{(E)}\ \frac53