To solve this problem using a graphing method, let's follow these steps:

1. Interpret the given function: You have a function that models the annual consumption of beef in tons, where $t$ represents the number of years since 2000, and the range of $t$ is from 0 to 17 (corresponding to the years 2000 to 2017). However, the function itself is not provided here.

2. Graphing the function: You would enter the given function into a graphing calculator with the specified window settings:

   • $x$-axis (representing time in years): $[0, 18]$
   • $y$-axis (representing beef consumption in tons): $[20000, 22000]$

3. Find where consumption is greater than 20,980 tons:

   • After graphing, you need to visually determine where the graph lies above the horizontal line $y = 20980$.
   • Use the intersection or zero function of your graphing calculator to find the points where the graph crosses $y = 20980$. These points will help you find the intervals.

4. Interval notation: Once you've identified the years when the consumption is greater than 20,980 tons, you will write the intervals based on those points, rounding the years to one decimal place.

Since I can't perform graphing directly, I recommend following these steps using a calculator and applying the logic above. Once you have the intersection points, you will see the range of years during which consumption exceeds 20,980 tons.

Example Format (to guide your answer):

If the graph shows that consumption is above 20,980 tons from year $t_1$ to $t_2$, the answer will be written in interval notation as: $(t_1, t_2)$

Would you like further assistance on any specific part of the process?

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Next Steps:

1. Would you like a sample function to practice graphing?
2. Do you need help inputting values into your graphing calculator?
3. Want an explanation on how to find the intersection points?
4. Need help with rounding or interval notation?
5. Want a deeper explanation on interpreting function behavior over time?

Tip: Always check your window settings carefully to ensure they align with the problem's requirements when graphing.