1. **State the problem:** Solve the equation $$\frac{21}{5x} = 2$$ for $x$. 2. **Formula and rules:** To solve for $x$, we need to isolate $x$ on one side of the equation. We can do this by multiplying both sides by $5x$ to eliminate the denominator. 3. **Multiply both sides by $5x$:** $$\frac{21}{5x} \times 5x = 2 \times 5x$$ This simplifies to: $$21 = 10x$$ 4. **Solve for $x$:** Divide both sides by 10: $$x = \frac{21}{10}$$ 5. **Final answer:** $$x = 2.1$$ This means the value of $x$ that satisfies the equation is $2.1$.