1. **Problem statement:** An IV releases 11 milliliters of medication every 2 minutes to a patient. After 180 minutes, the bag has 220 ml remaining. We need to write an equation representing this situation. 2. **Define variables:** - Let $x$ = time in minutes - Let $y$ = milliliters of medication left in the bag 3. **Understand the rate:** The IV releases 11 ml every 2 minutes, so the rate of release per minute is: $$\frac{11}{2} = 5.5 \text{ ml per minute}$$ 4. **Form the linear equation:** The amount of medication decreases over time, so the equation has the form: $$y = y_0 - \text{rate} \times x$$ where $y_0$ is the initial amount and $x$ is time. 5. **Use given data to find initial amount $y_0$:** At $x=180$ minutes, $y=220$ ml. Substitute into the equation: $$220 = y_0 - 5.5 \times 180$$ Calculate: $$220 = y_0 - 990$$ Add 990 to both sides: $$y_0 = 220 + 990 = 1210$$ 6. **Final equation:** $$y = 1210 - 5.5x$$ 7. **Interpretation:** This equation shows that the medication starts at 1210 ml and decreases by 5.5 ml every minute. 8. **Graph description:** The graph is a straight line with a negative slope of -5.5, starting at $y=1210$ when $x=0$ and decreasing as time increases.