document.write( "Question 1096284: Henry's sister is 3 years younger than Henry. The product of their ages is 180.
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Algebra.Com's Answer #710743 by ikleyn(52781) $\"\"$ $\"About$

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document.write( "15 and 12 are two factors of 180 that differ in 3 units and whose product is exactly 180.\r\n" );
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document.write( "And there are no other such positive numbers.\r\n" );
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document.write( "(But still there are negative: -15 and -12).\r\n" );
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document.write( "Notice that I presented you the MENTAL solution.\r\n" );
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document.write( "There is another way to solve the problem using equation:\r\n" );
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document.write( "x*(x+3) = 180,\r\n" );
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document.write( "x^2 + 3x - 180 = 0,\r\n" );
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document.write( "(x-12)*(x+15) = 0,\r\n" );
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document.write( "which gives the roots  x = 12 and x = -15.\r\n" );
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