Answer
$g(x)$ has zeros at $x=\frac{r_1}{2},~x=\frac{r_2}{2},~and~x=\frac{r_3}{2}$
Work Step by Step
We have that: $f(r_1)=f(r_2)=f(r_3)=0$
$g(\frac{r_1}{2})=f(2\frac{r_1}{2})=f(r_1)=0$
$g(\frac{r_2}{2})=f(2\frac{r_2}{2})=f(r_2)=0$
$g(\frac{r_3}{2})=f(2\frac{r_3}{2})=f(r_3)=0$
