1. The problem is to solve an equation by substituting or "plucking in" the variable $r$ first. 2. Generally, when solving equations, substituting a variable means replacing it with a given value or expression to simplify the equation. 3. Without a specific equation, the general approach is: - Identify the equation involving $r$. - Substitute the given value or expression for $r$. - Simplify the resulting expression step-by-step. 4. For example, if the equation is $y = 3r + 5$ and $r = 2$, then substituting $r$ gives: $$y = 3 \times 2 + 5$$ 5. Simplify: $$y = 6 + 5 = 11$$ 6. This method helps to find the value of $y$ by first plugging in $r$. Since no specific equation was provided, this is the general explanation of how to "pluck in $r$ first."