Question 63494
1.) Set up three equations.
A+B+C=9000
2A=B+C
0.1A+0.09B+0.06C=0.13*9000
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Matrices:

1......1......1
2.....-1.....-1
0.10..0.09..0.06
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9000
0
1170
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Multiply the inverse of the 3 x 3 matrix times the 3 x 1 matris
to get the solution matrix:
A=3000
B=17000
C=-11000
Comment:  This doesn't make any sense.  
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2.) Solve using any of the differnt types of matrix equations, and state which method you are using. 
Not sure what they mean by this.
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Cheers,
Stan H.