Question

Write equations that represent the cost of developing a roll of film at each lab.

Short answer

The equation that represent cost of developing a roll film at The Photo Lab is $y=3.20x+8$ and cost of developing a roll film at The Photo Lab is $y=2.60x+10$.

Step-by-step solution

Step-1 – Interpret the data

According to the question, a roll of film is developed at two places.

The cost of developing a roll of film includes two things cost of roll and cost of print.

At the Photo Lab the cost is $3.20 per roll plus 8 per print.

At the Specialty Photos the cost is $2.60 per roll plus 10 per print.

Step-2 – Define the variables

Consider two variables x and y.

Denote the cost of each roll by x and total cost of developing the roll film by y.

Step-3 – Build the equations

Let the lab use x rolls.

At the Photo Lab the cost is $3.20 per roll plus 8 per print.

Therefore, the cost of developing roll of film is expressed below.

$y=3.20x+8$

At the Specialty Photos the cost is $2.60 per roll plus 10 per print.

Therefore, the cost of developing roll of film is expressed below.

$y=2.60x+10$

Thus, the equations that represent cost of developing a roll of film are $y=3.20x+8$ and $y=2.60x+10$ at the Photo Lab and Specialty Photos respectively.