document.write( "Question 28862: \"x%2B3y=6\"
\n" ); document.write( "\"x-3y=12\"
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Algebra.Com's Answer #15787 by sdmmadam@yahoo.com(530)\"\" \"About 
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x+3y=6 ----(1)
\n" ); document.write( "x-3y=12 ----(2)
\n" ); document.write( "We observe that if we add the two equations,since the coefficients of y are eqaul in magnitude and opposite in sign,the y-variable gets eliminated.
\n" ); document.write( "(1) +(2) implies
\n" ); document.write( "(x+x)+(3y-3y) = (6+12)
\n" ); document.write( "2x+0 =18
\n" ); document.write( "2x=18
\n" ); document.write( "x=18/2 = 9
\n" ); document.write( "Putting x=9 in (1)
\n" ); document.write( "x+3y = 6
\n" ); document.write( "9+3y =6
\n" ); document.write( "3y = 6-9
\n" ); document.write( "3y = -3
\n" ); document.write( "y = -3/3 =-1
\n" ); document.write( "Answer: x=9 and y = -1
\n" ); document.write( "Verification: checking x=9 and y = -1 in (2)
\n" ); document.write( "LHS = x-3y = 9- 3X(-1) = 9+3 = 12 = RHS
\n" ); document.write( "Therefore our values are correct
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