SOLUTION: A teacher gives a final exam and the scores range from 40 to 80. The teacher decides to scale the exam in order to make the scores range from 60 to 90. Let x represent the origina

Question 67290: A teacher gives a final exam and the scores range from 40 to 80. The teacher decides to scale the exam in order to make the scores range from 60 to 90. Let x represent the original score and let y represent a converted score.

Use the ordered pairs (40, 60) and (80, 90) to write the equation that the teacher will use to scale the exam scores.

Answer by ankor@dixie-net.com(22740) (Show Source): You can put this solution on YOUR website!
A teacher gives a final exam and the scores range from 40 to 80. The teacher decides to scale the exam in order to make the scores range from 60 to 90. Let x represent the original score and let y represent a converted score.
:
Use the ordered pairs (40, 60) and (80, 90) to write the equation that the teacher will use to scale the exam scores.
:
Subtract 40 from the old score, (all scores are above 40)
Old score range of 40, compressed into a range of 30.
:
In equation form:
y = .75(x-40) + 60
y = .75x - 30 + 60
y = .75x + 30
:
The graph should look like something like this:

:
you can check the equation using the given ordered pairs
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