1. **Stating the problem:** Solve the system of equations: $$\begin{cases} x + 5y = 72 \\ x = 7y \end{cases}$$ 2. **Formula and rules:** We use substitution since $x$ is already expressed in terms of $y$. 3. **Substitute $x = 7y$ into the first equation:** $$7y + 5y = 72$$ 4. **Combine like terms:** $$12y = 72$$ 5. **Solve for $y$ by dividing both sides by 12:** $$y = \frac{72}{12}$$ 6. **Simplify the fraction:** $$y = 6$$ 7. **Substitute $y = 6$ back into $x = 7y$ to find $x$:** $$x = 7 \times 6 = 42$$ 8. **Final answer:** $$\boxed{(x, y) = (42, 6)}$$