Question

The elevation of your plot of land is 2 feet below sea level. You add 7 feet of dirt to your land. Write an expression to represent this situation. What is the new elevation of your land? Explain how you found your answer.

a) Elevation = 2 + 7; Explanation: Add the initial elevation and the added dirt.
b) Elevation = 7 - 2; Explanation: Subtract the initial elevation from the added dirt.
c) Elevation = 2 - 7; Explanation: Subtract the added dirt from the initial elevation.
d) Elevation = 2 + 7^2; Explanation: Square the added dirt and add it to the initial elevation.

Answer 1

The correct expression is 'Elevation = -2 + 7' and, after performing the addition, the new elevation of the plot of land is 5 feet above sea level, moving from below to above sea level after adding the dirt.

Step-by-step explanation:

The situation describes a change in elevation due to the addition of dirt to a plot of land initially below sea level. The correct expression to represent the new elevation after adding 7 feet of dirt to the original elevation, which is 2 feet below sea level, would be:

Elevation = -2 + 7

The initial elevation is 2 feet below sea level, which is represented by -2. When 7 feet of dirt is added, we represent this by +7. Adding these together, the new elevation of the land would be 5 feet above sea level. Therefore, the new elevation is 5 feet above sea level.

It is important to note that the minus sign indicates that the original elevation is below sea level, so when we add the 7 feet, we are essentially moving from a negative elevation (below sea level) to a positive elevation (above sea level).