document.write( "Question 958358: xy=4
\n" ); document.write( "x^2+y^2=8\r
\n" ); document.write( "\n" ); document.write( "How do I solve this system by the substitution method? \n" ); document.write( "

Algebra.Com's Answer #585722 by MathLover1(20849) $\"\"$ $\"About$

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\n" ); document.write( " $\"xy=4\"$ ...........(1)
\n" ); document.write( " $\"x%5E2%2By%5E2=8\"$ .......(2)
\n" ); document.write( "--------------------\r
\n" ); document.write( "\n" ); document.write( " $\"xy=4\"$ ...........(1)...solve for $\"x\"$ \r
\n" ); document.write( "\n" ); document.write( " $\"x=4%2Fy\"$ ..........substitute in (2)\r
\n" ); document.write( "\n" ); document.write( " $\"%284%2Fy%29%5E2%2By%5E2=8\"$ .......(2) solve for $\"y\"$ \r
\n" ); document.write( "\n" ); document.write( " $\"16%2Fy%5E2%2By%5E2=8\"$ \r
\n" ); document.write( "\n" ); document.write( " $\"%2816%2By%5E4%29%2Fy%5E2=8\"$ \r
\n" ); document.write( "\n" ); document.write( " $\"16%2By%5E4=8y%5E2\"$ \r
\n" ); document.write( "\n" ); document.write( " $\"y%5E4-8y%5E2%2B16=0\"$ \r
\n" ); document.write( "\n" ); document.write( " $\"%28y%5E2%29%5E2-8y%5E2%2B4%5E2=0\"$ \r
\n" ); document.write( "\n" ); document.write( " $\"%28y%5E2-4%29%5E2=0\"$ \r
\n" ); document.write( "\n" ); document.write( " $\"%28y%5E2-4%29%28y%5E2-4%29=0\"$ \r
\n" ); document.write( "\n" ); document.write( " $\"%28y-2%29%28y%2B2%29%28y-2%29%28y%2B2%29=0\"$ \r
\n" ); document.write( "\n" ); document.write( "solutions: two double solutions\r
\n" ); document.write( "\n" ); document.write( "if $\"%28y-2%29=0\"$ => $\"y=2\"$
\n" ); document.write( "if $\"%28y%2B2%29=0\"$ => $\"y=-2\"$ \r
\n" ); document.write( "\n" ); document.write( "now find $\"x\"$ \r
\n" ); document.write( "\n" ); document.write( " $\"x=4%2Fy\"$ substitute => $\"y=2\"$ \r
\n" ); document.write( "\n" ); document.write( " $\"x=4%2F2\"$ \r
\n" ); document.write( "\n" ); document.write( " $\"x=2\"$ \r
\n" ); document.write( "\n" ); document.write( "and\r
\n" ); document.write( "\n" ); document.write( " $\"x=4%2Fy\"$ substitute => $\"y=-2\"$ \r
\n" ); document.write( "\n" ); document.write( " $\"x=4%2F-2\"$ \r
\n" ); document.write( "\n" ); document.write( " $\"x=-2\"$ \r
\n" ); document.write( "\n" ); document.write( "so,
\n" ); document.write( " $\"x=2\"$ , $\"y=2\"$
\n" ); document.write( "or
\n" ); document.write( " $\"x=-2\"$ , $\"y=-2\"$ \r
\n" ); document.write( "\n" ); document.write( " \n" ); document.write( "

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