SOLUTION: "We are comparing two plotters. An HP and a Canon. The HP lists for $3427 and the Canon for $4995. A black cartridge for the HP is $56, The black for Canon is $81. How many cartrid

Algebra ->  Customizable Word Problem Solvers  -> Misc -> SOLUTION: "We are comparing two plotters. An HP and a Canon. The HP lists for $3427 and the Canon for $4995. A black cartridge for the HP is $56, The black for Canon is $81. How many cartrid      Log On

Ad: Over 600 Algebra Word Problems at edhelper.com


   



Question 823785: "We are comparing two plotters. An HP and a Canon. The HP lists for $3427 and the Canon for $4995. A black cartridge for the HP is $56, The black for Canon is $81. How many cartridges for each one will be needed before the price comes out the same?"
This is a real-life application of the algebra I learned in school, and I can probably solve it on my own once I figure out how to set it up. This is what I have tried:
3427+56x=4995+81y
This just comes out to the solution 4994=4995 and I don't really understand why.

Answer by TimothyLamb(4379) About Me  (Show Source):
You can put this solution on YOUR website!
---
x = number of cartridges
y = cost of operation
---
canon:
y = 81x + 4995
---
hp:
y = 56x + 3427
---
y = 81x + 4995
y = 56x + 3427
---
put the system of linear equations into standard form
---
81x - y = -4995
56x - y = -3427
---
copy and paste the above standard form linear equations in to this solver:
https://sooeet.com/math/system-of-linear-equations-solver.php
---
answer:
x= -62.72
y= -85.32
---
the "cost of operation" for both plotters is the same but "negative" ($-85.32) when you purchase a "negative" number of cartridges (-62.72) !
---
that sounds strange, but there's a simple explanation.
---
regardless how many cartridges you purchase for either plotter, the Canon will always be more expensive to operate than the HP.
---
the graphs of the cost lines of the two plotters make that very clear.
---
notice that the lines intersect at x= -62.72 y= -85.32, but the lines diverge for x > 0
---
graph:
---
+graph%28+300%2C+300%2C+-100%2C+100%2C+-1000%2C+7000%2C+81x+%2B+4995%2C+56x+%2B+3427%29+
---
Solve and graph linear equations:
https://sooeet.com/math/linear-equation-solver.php
---
Solve quadratic equations, quadratic formula:
https://sooeet.com/math/quadratic-formula-solver.php
---
Solve systems of linear equations up to 6-equations 6-variables:
https://sooeet.com/math/system-of-linear-equations-solver.php