document.write( "Question 830903: Robert is 15 years older than his brother Stan. However, \"y\" years ago, Robert was as twice as old as Stan. If Stan is now \"b\" years old and b>y, find the value of (b-y). \n" ); document.write( "
Algebra.Com's Answer #501000 by Edwin McCravy(20056)\"\" \"About 
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document.write( "Read way down where it says:\r\n" );
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\n" ); document.write( "Stan is now \"b\" years old
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document.write( "So b = Stan's present age\r\n" );
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\n" ); document.write( "Robert is 15 years older than his brother Stan.
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document.write( "So b+15 = Robert's present age\r\n" );
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\n" ); document.write( "\"y\" years ago, Robert was...
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document.write( "Stop here and think:\r\n" );
document.write( "\"y\" years ago, Robert was (b+15)-y or b+15-y \r\n" );
document.write( "and also y years ago, Stan was b-y\r\n" );
document.write( "Now read the whole sentence:\r\n" );
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\n" ); document.write( "\"y\" years ago, Robert was twice as old as Stan.
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document.write( "So\r\n" );
document.write( "b+15-y = 2(b-y)\r\n" );
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\n" ); document.write( "If... b>y,
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document.write( "That only tells us that \"b-y\" is a positive number, for if\r\n" );
document.write( "b were smaller and y were larger it would be negative.\r\n" );
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\n" ); document.write( "find the value of (b-y).
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document.write( "b+15-y = 2(b-y)\r\n" );
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document.write( "Swap the \"+15\" and the \"-y\" to get \"-y\" next to \"b\"\r\n" );
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document.write( "b-y+15 = 2(b-y)\r\n" );
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document.write( "Put parentheses around \"b-y\"\r\n" );
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document.write( "(b-y)+15 = 2(b-y)\r\n" );
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document.write( "Think of \"(b-y)\" as though it were just a single letter like \"x\"\r\n" );
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document.write( "Subtract \"(b-y)\" from both sides of the equation\r\n" );
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document.write( "15 = 2(b-y) - (b-y)\r\n" );
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document.write( "Think of (b-y) as 1(b-y)\r\n" );
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document.write( "15 = 2(b-y) - 1(b-y)\r\n" );
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document.write( "TWO \"(b-y)\"'s minus ONE \"(b-y)\" leave ONE \"(b-y)\" \r\n" );
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document.write( "      15 = 1(b-y)\r\n" );
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document.write( "      15 = b-y\r\n" );
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document.write( "Answer = 15.\r\n" );
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document.write( "Edwin
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