## Precalculus: Concepts Through Functions, A Unit Circle Approach to Trigonometry (3rd Edition)

$\text{(c) }y=\frac{x}{2}$
The graph contains the points $(0,0)$ and $(8,4)$. . Note that both poionts satisfy the equation $y=\frac{x}{2}$: $0=\frac{0}{2}$ $4=\frac{8}{2}$ Thus, the graph representa the equation $y=\frac{x}{2}$.