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8) Solve the equation:

\[
\frac{50}{5} + \frac{c}{5} = \frac{36}{5}
\]

Select all of the situations that could be modeled by a linear equation.

A. The Barton family is driving at a rate of 62 miles per hour.

B. Mr. Dominguez invested \$1000. This money is growing at a rate of 4% per year.

C. A tree was 10 feet tall when purchased. It is growing at a rate of 2 feet per year.

D. Tim dropped a coin off a bridge. It is falling at a rate of 9.8 meters per second squared.

E. The amount of people in a stadium is decreasing at a rate of 45% every 10 minutes.

Answer :

To solve the equation [tex]\(\frac{50}{5} + \frac{c}{5} = \frac{36}{5}\)[/tex], follow these steps:

1. Simplify the fractions:

- [tex]\(\frac{50}{5}\)[/tex] simplifies to [tex]\(10\)[/tex].
- [tex]\(\frac{36}{5}\)[/tex] stays as [tex]\(\frac{36}{5}\)[/tex] since it can't be simplified further.

So the equation becomes:
[tex]\[
10 + \frac{c}{5} = \frac{36}{5}
\][/tex]

2. Eliminate the fraction: To clear the fractions, multiply the entire equation by 5:

[tex]\[
5 \times 10 + 5 \times \frac{c}{5} = 5 \times \frac{36}{5}
\][/tex]

This simplifies to:

[tex]\[
50 + c = 36
\][/tex]

3. Solve for [tex]\(c\)[/tex]: Subtract 50 from both sides of the equation to isolate [tex]\(c\)[/tex]:

[tex]\[
c = 36 - 50
\][/tex]

4. Calculate:

[tex]\[
c = -14
\][/tex]

Therefore, the solution is [tex]\(c = -14\)[/tex].

Now, regarding the situations that can be modeled by linear equations:

- Situation A: The Barton family is driving at a constant speed (62 miles per hour). This is a linear situation because distance increases steadily over time.

- Situation B: The money grows at a constant rate of 4% per year. This is not linear; it's exponential because the growth rate applies to the increasing total over time.

- Situation C: A tree grows a consistent amount each year (2 feet per year). This is linear because its height increases by a fixed amount each year.

- Situation D: The coin is falling at a rate of 9.8 meters per second squared, indicating acceleration. This is not linear, as it's related to the quadratic relationship of acceleration.

- Situation E: The number of people decreases by a percentage every 10 minutes. This is exponential decay, not linear.

Thus, the situations that can be modeled by a linear equation are A and C.

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