SOLUTION: Requesting assistance writing an equation for the following problem: 4 tickets sell for $63.00 6 tickets sell for $91.00 Can an equation be written for calculating the cost

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Question 127160: Requesting assistance writing an equation for the following problem:
4 tickets sell for $63.00
6 tickets sell for $91.00
Can an equation be written for calculating the cost of any number of tickts?
Thanks! Jon
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
What you've got is 2 points (x,y) The points are:
(4,63) and (6,61). Given these 2 points, you can plot a line
through them. The line looks like y+=+mx+%2B+b
You need to find m and b
For (4,63)
63+=+m%2A4+%2B+b
For (6,61)
61+=+m%2A6+%2B+b
-----------------
multiply the 2nd equation by -1 and add them
63+=+m%2A4+%2B+b
-61+=+-m%2A6+-+b
-------------------
2+=+-m%2A2+
m+=+-1
Now find b
61+=+-1%2A6+%2B+b
b+=+67
The equation through the 2 points is y+=+-x+%2B+67
check answer:
Does the line go through the given points?
Try (4,63)
y+=+-x+%2B+67
y+=+-4+%2B+67
y+=+63
Try (6,61)
y+=+-x+%2B+67
y+=+-6+%2B+67
y+=+61
OK