Answer: r = - 20
Step-by-step explanation:
[tex]-4 = \frac{r}{20} - 5[/tex]
[tex]\frac{r}{20} = 4-5[/tex]
[tex]\frac{r}{20}=-1[/tex]
[tex]\frac{r}{20}*20 = -1 * 20[/tex]
[tex]r = -20[/tex]
