1. Stating the problem: Solve the equation $$17r - 13r = 20$$ for $$r$$. 2. Combine like terms on the left side: $$17r - 13r = (17 - 13)r = 4r$$ 3. The equation becomes: $$4r = 20$$ 4. To isolate $$r$$, divide both sides by 4: $$\frac{\cancel{4}r}{\cancel{4}} = \frac{20}{4}$$ 5. Simplify the right side: $$r = 5$$ Final answer: $$r = 5$$