The question in the image is:

"The value of your stock investment in a certain company decreased 30% over the last year. If the value of your stock investment is $4,000 today, then what was the value of your stock investment a year ago? Round your answer to the nearest cent, if necessary."

To solve this problem, we can work backward from the current value ($4,000) and account for the 30% decrease.

Let $x$ represent the value of the investment a year ago.

If the investment decreased by 30%, then the value today is 70% (or 0.70) of what it was a year ago. This gives the equation:

$0.70 \times x = 4000$

To find $x$, we divide both sides by 0.70:

$x = \frac{4000}{0.70} = 5714.29$

So, the value of the stock investment a year ago was $5,714.29.

Would you like more details on the solution or have any further questions?

Here are 5 related questions:

1. What is the formula to calculate percentage decrease or increase in investments?
2. How do you calculate future value based on percentage growth over time?
3. What would the value be after a further 20% decrease this year?
4. How would you reverse a percentage decrease if the percentage changes?
5. How can compound percentage changes affect investment over multiple years?

Tip: When reversing a percentage decrease, always divide the current value by (1 - percentage decrease as a decimal).