document.write( "Question 228281: Use substitution with the two equations and determine the points of intersection.\r
\n" ); document.write( "\n" ); document.write( "y=x^2-1
\n" ); document.write( "y=x \n" ); document.write( "

Algebra.Com's Answer #169505 by checkley77(12844) $\"\"$ $\"About$

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y=x^2-1
\n" ); document.write( "y=x
\n" ); document.write( "REPLACING Y WITH X IN THE FIRST EQUATION WE GET:
\n" ); document.write( "X=X^2-1
\n" ); document.write( "X^2-X-1=0
\n" ); document.write( " $\"x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+\"$
\n" ); document.write( "X=(1+-SQRT[-1^2-4*1*-1])/2*1
\n" ); document.write( "X=(1+-SQRT1+4)/2
\n" ); document.write( "X=(1+-SQRT5)/2
\n" ); document.write( "X=(1+-2.236) /2
\n" ); document.write( "X=(1+2.236)/2
\n" ); document.write( "X=3.236/2
\n" ); document.write( "X=1.618 ANS. Y=1.618 ANS.
\n" ); document.write( "X=(1-2.236)/2
\n" ); document.write( "X=-1.236/2
\n" ); document.write( "X=-.618 ANS. Y=-.618 ANS
\n" ); document.write( "PROOF:
\n" ); document.write( "1.618=1.618^2-1
\n" ); document.write( "1.618=2.618-1
\n" ); document.write( "1.618=1.618
\n" ); document.write( "-.618=-.618^2-1
\n" ); document.write( "-.618=.382-1
\n" ); document.write( "-.618=-.618 \n" ); document.write( "

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