document.write( "Question 52977: if a-b=5 and ab=-1, what is the numerical value of (2a+3b-2ab)-(a+4b+ab)-(3ab+2b-2a) \n" ); document.write( "
Algebra.Com's Answer #35339 by AnlytcPhil(1806)\"\" \"About 
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if a-b=5 and ab=-1, what is the numerical\r\n" );
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document.write( "(2a+3b-2ab)-(a+4b+ab)-(3ab+2b-2a)\r\n" );
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document.write( "Remove the parentheses:\r\n" );
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document.write( "2a+3b-2ab-a-4b-ab-3ab-2b+2a\r\n" );
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document.write( "Put like terms together:\r\n" );
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document.write( "2a-a+2a + 3b-4b-2b - 2ab-ab-3ab\r\n" );
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document.write( "Combine like terms:\r\n" );
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document.write( "3a - 3b -6ab\r\n" );
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document.write( "Factor 3 out of first two terms:\r\n" );
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document.write( "3(a - b) - 6ab\r\n" );
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document.write( "Substitute (5) for (a - b) and (-1) for ab \r\n" );
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document.write( "3(5) - 6(-1)\r\n" );
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document.write( "15 + 6\r\n" );
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document.write( "21\r\n" );
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document.write( "That's the easy way.  \r\n" );
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document.write( "(The hard way would be to first solve the system\r\n" );
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document.write( "a - b =  5\r\n" );
document.write( "   ab = -1\r\n" );
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document.write( "and then substitute.)\r\n" );
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document.write( "Edwin
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