### Practice & Problem Solving

1. Max spent all his money and now has no money left. He had [tex]$s$[/tex] dollars before his purchase. Write an equation to represent this situation.

2. The temperature was 8°F. It dropped to 0°F. What does -8°F represent in this context?

3. An airplane descended 4,000 feet before landing. The integer that represents how many feet the airplane was above the ground before its descent is 4,000 feet.



Answer :

Let's go through each problem step by step:

Problem 7: Max's Money

Max had an initial amount of money, [tex]\( s \)[/tex], which is 3 dollars. He spent all his money, so the amount he has left is 0 dollars. We can summarize the information as follows:
- Initial amount of money (s): 3 dollars
- Amount left after spending (money_left): 0 dollars
- Amount he spent (ser): 3 dollars

So, the answers are:
- The amount of money left: 0 dollars
- The amount Max spent (ser): 3 dollars

Problem 8: Temperature Drop

The initial temperature was 8°F. It dropped to -8°F, which indicates a change or drop in temperature.

To find the change in temperature:
- Initial temperature: 8°F
- Final temperature after the drop: -8°F

The change in temperature is:
[tex]\[ \text{Change in temperature} = \text{Final temperature} - \text{Initial temperature} \][/tex]
[tex]\[ \text{Change in temperature} = -8°F - 8°F = -16°F \][/tex]

Thus, the temperature dropped by 16°F.

Problem 3: Airplane's Descent

An airplane descended 4,000 feet before landing. To determine the height of the airplane above the ground before its descent, we consider the descent as a decrease in height.

Let's denote the initial height of the airplane above the ground as [tex]\( h \)[/tex]. The airplane descended 4,000 feet, and for it to land (reach ground level), we set the equation:

[tex]\[ h - 4,000 \text{ feet} = 0 \text{ feet} \][/tex]

By solving for [tex]\( h \)[/tex]:
[tex]\[ h = 4,000 \text{ feet} \][/tex]

So, the airplane was 4,000 feet above the ground before it started its descent.

In summary:
- For Problem 7: The amount of money left is 0 dollars, and Max spent 3 dollars.
- For Problem 8: The temperature dropped by 16°F.
- For Problem 3: The airplane was 4,000 feet above the ground before descending.