Multiply $2filpr$ by $ \dfrac{i}{r+2fi^2lp} $ to get $ \dfrac{2fi^2lpr}{2fi^2lp+r} $.

Step 1: Write $ 2filpr $ as a fraction by putting $ \color{red}{1} $ in the denominator.

Step 2: Multiply numerators and denominators.

Step 3: Simplify numerator and denominator.

$$ \begin{aligned} 2filpr \cdot \frac{i}{r+2fi^2lp} & \xlongequal{\text{Step 1}} \frac{2filpr}{\color{red}{1}} \cdot \frac{i}{r+2fi^2lp} \xlongequal{\text{Step 2}} \frac{ 2filpr \cdot i }{ 1 \cdot \left( r+2fi^2lp \right) } = \\[1ex] & \xlongequal{\text{Step 3}} \frac{ 2fi^2lpr }{ r+2fi^2lp } = \frac{2fi^2lpr}{2fi^2lp+r} \end{aligned} $$