document.write( "Question 445229: Here's my problem: I don't know how to write an algebraic equation to work this out. Please help, thank you very much.\r
\n" ); document.write( "\n" ); document.write( "John bought two computers. One desktop and one laptop. Before finance charges, the laptop cost $1000 more than the desktop. John paid for the computers using two different financing plans. For the desktop, the interest rate was 8.5% per year, and the laptop was 7.5% per year. The total finance charges for one year were $915. How much did the desktop computer cost before finance charges? \n" ); document.write( "
Algebra.Com's Answer #306762 by mananth(16946)\"\" \"About 
You can put this solution on YOUR website!
Laptop x Cost
\n" ); document.write( "Desktop ----------y Cost
\n" ); document.write( "x-y=1000 .............1
\n" ); document.write( "0.075x+0.085y=915 .............2
\n" ); document.write( "Eliminate y
\n" ); document.write( "multiply (1)by 0.085
\n" ); document.write( "Multiply (2) by 1
\n" ); document.write( "0.085 x -0.085 y = 85
\n" ); document.write( "0.075 x +0.085y = 915
\n" ); document.write( "Add the two equations
\n" ); document.write( "0.16 x= 1000
\n" ); document.write( "/ 0.16
\n" ); document.write( "x = 6,250.00
\n" ); document.write( "plug value of x in (1)
\n" ); document.write( "x-y=1000
\n" ); document.write( "6250-y= 1000
\n" ); document.write( "-y=1000 -6250
\n" ); document.write( "-y=-5250
\n" ); document.write( "y=5250.00
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