document.write( "Question 1122737: please help with this problem (500x+100y=325) (400x+150y=304) \n" ); document.write( "

Algebra.Com's Answer #738925 by MathTherapy(10552) $\"\"$ $\"About$

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\n" ); document.write( "please help with this problem (500x+100y=325) (400x+150y=304)
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This is a perfect example of what NOT TO DO when solving a system with large numbers and possibly fractional solutions.
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document.write( "One of these 2 people is WRONG, as it's most likely attributable to the fact that both converted to decimals, which is TOTALLY UNNECESSARY, and as in most cases and this,
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document.write( "such \"strategy,\" if you can call it that, can lead to possible confusion, and INCORRECT answers. This is the way it should be done:
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document.write( "500x + 100y = 325 ------ eq (i)
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document.write( "400x + 150y = 304 ------ eq (ii)
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document.write( "100x - 50y = 21 -------- Subtracting eq (ii) from eq (i) ------ eq (iii)
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document.write( "100x + 20y = 65 -------- Dividing eq (i) by 5 ------ eq (iv)
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document.write( "       70y = 44 -------- Subtracting eq (iii) from eq (iv)
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document.write( "Since it's too complex to substitute  (fraction that doesn't cancel nicely) into any of the 2 ORIGINAL equations - and could likely result in error(s) - we will ELIMINATE y as follows:
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document.write( "300x - 150y = 63 --- Multiplying eq (iii) by 3 ------- eq (v)
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document.write( "700x = 367 --------- Adding eqs (v) and (ii)
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document.write( "You don't have to go further and convert the fractions to decimals. It's TOTALLY UNNECESSARY; plus, you were NOT asked to do so. \n" );
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