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Old 09-25-2012, 09:36 AM
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ceptimus ceptimus is offline
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Join Date: Aug 2004
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Default Re: Homework Help Thread - Linear Algebra Edition

If you think of each row as an equation perhaps concerning the cost of some items, then multiplying by a fixed number doesn't tell you anything new:

(2 quarts of milk + 3 bagels cost $3.50) x 2 :rarrow: 4 quarts + 6 bagels cost $7.00 :shrug:

But when you combine multiplying a row and adding (or subtracting) from another independent row, then you can work out the cost of the individual items:

2 quarts + 3 bagels cost $3.50

7 quarts + 4 bagels cost $9.00

Now you can work out that a quart costs a dollar, and the bagels are fifty cents each: to do it formally you might multiply the first row by 4/3 and then subtract from the second row to eliminate the bagels from the result.
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Thanks, from:
Clutch Munny (09-26-2012), Dragar (10-03-2012), Ensign Steve (09-25-2012)
 
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