document.write( "Question 766749: if a+b = 65, a+c=63 and a+d=45 what will be the value of \"a\" if a+b+c+d=118 \n" ); document.write( "

Algebra.Com's Answer #467219 by ramkikk66(644) $\"\"$ $\"About$

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document.write( "if a+b = 65, a+c=63 and a+d=45 what will be the value of \"a\" if a+b+c+d=118\r
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document.write( "a + b = 65 (eqn 1)
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document.write( "a + c = 63 (eqn 2)
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document.write( "a + d = 45 (eqn 3)
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document.write( "a + b + c + d = 118 (eqn 4)\r
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document.write( "Adding eqns (1), (2), and (3), we get
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document.write( "3*a + b + c + d = 65 + 63 + 45 = 173
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document.write( "So, b + c + d = 173 - 3*a   (eqn 5)\r
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document.write( "Substituting for (b+c+d) in eqn (4)\r
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document.write( "a + 173 - 3*a = 118
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document.write( "2*a = 173 - 118 = 55
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document.write( "a = 
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document.write( "Now we can find b, c and d from the first 3 equations
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document.write( "b = 65 - a = 65 - 27.5 = 
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document.write( "c = 63 - a = 63 - 27.5 = 
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document.write( "d = 45 - a = 45 - 27.5 = \r
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document.write( "Check for correctness:
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document.write( "a + b + c + d = 27.5 + 37.5 + 35.5 + 17.5 = 118 (correct!)\r
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