document.write( "Question 457415: PLEASE HELP ASAP!
\n" ); document.write( "Solve the following problem by setting up and solving a system of three linear equations in three variables.
\n" ); document.write( "Part of $2,000 is invested at 12%, another part at 13%, and the remainder at 14%. The total yearly income from the three investments is $268. The sum of the amounts invested at 12% and 13% equals the amount invested at 14%. Determine how much is invested at each rate.
\n" ); document.write( "12% interest =$?
\n" ); document.write( "13% interest =$?
\n" ); document.write( "14% interest =$?
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Algebra.Com's Answer #313889 by mananth(16946)\"\" \"About 
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12%------------x
\n" ); document.write( "13%------------y
\n" ); document.write( "14%------------z\r
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\n" ); document.write( "\n" ); document.write( "x+y+z=2000--------------1
\n" ); document.write( "12x+13y+14z=268*100--------------2
\n" ); document.write( "x+y-z=0 --------------3
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\n" ); document.write( "consider equation 1 &2 Eliminate y
\n" ); document.write( "Multiply 1 by -13
\n" ); document.write( "Multiply 2 by 1
\n" ); document.write( "we get
\n" ); document.write( "-13x -13y-13z= -26000
\n" ); document.write( "12x+13y+14z=26800
\n" ); document.write( "Add the two
\n" ); document.write( "-x+z= 800 -------------4
\n" ); document.write( "consider equation 2 & 3 Eliminate y
\n" ); document.write( "-1x=800
\n" ); document.write( "Multiply 2 by x=-800
\n" ); document.write( "Multiply 3 by-13
\n" ); document.write( "we get
\n" ); document.write( "12x+13y+14z=26800
\n" ); document.write( "-13x-13y+13z=0
\n" ); document.write( "Add the two
\n" ); document.write( "-1x+27z=26800 -------------5 5
\n" ); document.write( "Consider (4) & (5) Eliminate x
\n" ); document.write( "Multiply 4 by -1
\n" ); document.write( "Multiply (5) by 1
\n" ); document.write( "we get
\n" ); document.write( "x-z=-800
\n" ); document.write( "-x+27z= 26800
\n" ); document.write( "Add the two
\n" ); document.write( "26z=26000
\n" ); document.write( "/26
\n" ); document.write( "z=1000----14%
\n" ); document.write( "Plug the value of z in 5
\n" ); document.write( "-x+27000=26800
\n" ); document.write( "-x=-200
\n" ); document.write( "x=200----12%
\n" ); document.write( "plug value of x & z in 1
\n" ); document.write( "200+y+1000=2000
\n" ); document.write( "y=-200+ -1000+ 2000
\n" ); document.write( "y=800----13%
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