1. **Problem:** Find the constant of variation if $y$ varies directly as $x$ and $y=35$ when $x=5$. Write the direct variation equation. 2. **Formula:** For direct variation, $y=kx$ where $k$ is the constant of variation. 3. **Step 1:** Use given values to find $k$: $$35 = k \times 5$$ $$k = \frac{35}{5} = 7$$ 4. **Step 2:** Write the equation: $$y = 7x$$ This means $y$ increases 7 times as $x$ increases. --- **Summary:** The constant of variation is $7$ and the equation is $y=7x$.