Answer:
R = (K/3) + (A/F)
Explanation:
The goal is to isolate the r on one side.
The first step is to distribute the f on the right side of the equation.
a=rf+kr/3
Then, we should subtract rf from both sides
a-rf=kf/3
Next we need to subtract a from both sides
-rf=kf/3-a
Lastly, we should divide both sides by -f
r=-k/3+a/f