document.write( "Question 15519: Please solve the following system of equations:\r
\n" ); document.write( "\n" ); document.write( "x + y = -1\r
\n" ); document.write( "\n" ); document.write( "1/x + 1/y = 1/2\r
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\n" ); document.write( "\n" ); document.write( "I've tried cross multiplying and all sorts to eliminate one of the unknowns, but have just made things worse.\r
\n" ); document.write( "\n" ); document.write( "Please help. \n" ); document.write( "
Algebra.Com's Answer #7690 by vasu2qute(17)\"\" \"About 
You can put this solution on YOUR website!
Given: x + y =-1 ----(1)
\n" ); document.write( " 1/x+1/y=1/2 -----(2)
\n" ); document.write( "1/x+1/y=1/2 ===> (x+y)/xy =1/2
\n" ); document.write( " x+y = xy/2 (x+y=-1 according to Equation 1)
\n" ); document.write( " -1 = xy/2 (Substituting x+y with -1 )
\n" ); document.write( " xy= -2
\n" ); document.write( " We know that (x-y)^2 = (x+y)^2-4xy
\n" ); document.write( " = (-1)^2 -4(-2)
\n" ); document.write( " = 1 -(-8)=1+8=9
\n" ); document.write( " (x-y)^2 = 9
\n" ); document.write( " therefore x - y = 3 ------(3)
\n" ); document.write( " x + y = -1 ------(1)
\n" ); document.write( "adding (3)&(1) we get 2x = 2
\n" ); document.write( " x = 1\r
\n" ); document.write( "\n" ); document.write( " x + y = -1
\n" ); document.write( " 1 + y = -1
\n" ); document.write( " y = -1 -1 = -2
\n" ); document.write( "therefore x=1 , y= -2\r
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