document.write( "Question 1061541: Please help me solve this by using the substitution method. Thank you! \r
\n" ); document.write( "\n" ); document.write( " $\"+x%5E2%2By%5E2=90+\"$ \r
\n" ); document.write( "\n" ); document.write( " $\"+y=sqrt%28x%29+\"$
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Algebra.Com's Answer #676320 by ikleyn(52777) $\"\"$ $\"About$

You can put this solution on YOUR website!
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\n" ); document.write( "Please help me solve this by using the substitution method. Thank you! \r
\n" ); document.write( "\n" ); document.write( " $\"+x%5E2%2By%5E2=90+\"$ \r
\n" ); document.write( "\n" ); document.write( " $\"+y=sqrt%28x%29+\"$
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document.write( " = 90,    (1)\r\n" );
document.write( "y = .         (2)\r\n" );
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document.write( "Square equation (2) (both sides). You will get\r\n" );
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document.write( " = x.\r\n" );
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document.write( "Using this, replace  by \"x\" in the equation (2). You will get\r\n" );
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document.write( " = 90,      (1')   or\r\n" );
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document.write( " = 0.\r\n" );
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document.write( "Solve by using the quadratic formula. You will get\r\n" );
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document.write( " =  = .\r\n" );
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document.write( "Thus  = 9,   = -10.\r\n" );
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document.write( "Since \"x\" under the square root must be non-negative, only the root x= 9 survives.\r\n" );
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document.write( "Then y =  = +/- 3.\r\n" );
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document.write( "Answer. There are 2 solutions: (x,y) = (9,3)  and  (x,y) = (9,-3).\r\n" );
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