1. **State the problem:** Write the equation of a line in slope-intercept form given the slope and y-intercept. 2. **Recall the slope-intercept form:** The equation of a line is given by $$y = mx + b$$ where $m$ is the slope and $b$ is the y-intercept. 3. **Substitute the given values:** Here, slope $m = -\frac{1}{2}$ and y-intercept $b = 0$. 4. **Write the equation:** $$y = -\frac{1}{2}x + 0$$ 5. **Simplify:** Since adding zero does not change the value, the equation simplifies to $$y = -\frac{1}{2}x$$ This is the slope-intercept form of the line with slope $-\frac{1}{2}$ and y-intercept $0$.