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x^4-5x^2+6=0
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\n" ); document.write( "y^2-5y+6=0
\n" ); document.write( "(y-3)(y-2)=0
\n" ); document.write( "y=3,2
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document.write( "y=x^2
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document.write( "therefore,
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document.write( "x^2=3,x^2=2
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document.write( "x=sqrt(3),x=sqrt(2)
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document.write( "This gives us all the four values of x
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document.write( "How?
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document.write( "For example sqrt(16)=-4,+4
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document.write( "This is because when a number is squared,
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document.write( "-*-=+ and +*+=+
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document.write( "In other words,a negative number squared is positive,a positive number squared is also positive,so -4 or +4 squared will give the same result.
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document.write( "So our correct answer is:
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document.write( "x=+sqrt(3),-sqrt(3),+sqrt(2),-sqrt(2)
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document.write( "
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document.write( "Hope this helps,
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document.write( "Prabhat