The equation provided is:

$S - 1.7x = 5.1$

Where:

• $S$ is the amount of sales of statins in billions of dollars.
• $x$ is the number of years after 1998.

We are asked to determine the value of $S$ in 2017. To do this, first calculate $x$, which represents the number of years after 1998:

$x = 2017 - 1998 = 19$

Now, substitute $x = 19$ into the equation:

$S - 1.7(19) = 5.1$

Simplifying:

$S - 32.3 = 5.1$

Now solve for $S$:

$S = 5.1 + 32.3 = 37.4$

Thus, the people in the U.S. will spend $37.4 billion on statins in 2017.

Would you like further details or clarifications on this?

Here are five related questions to explore:

1. How would the equation change if the annual spending rate on statins changed?
2. Can this model be used for future predictions, say for the year 2025?
3. What assumptions are made when using linear models like this one?
4. How does the $1.7 billion yearly decrease in spending affect long-term projections?
5. Can we derive the year when statin sales were expected to hit zero based on this model?

Tip: Always double-check units when solving word problems—whether the result is in billions, millions, or another unit is important for accurate interpretation!