Question

x =) 9-4 root 5
find the answer fast
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Answer 1

X=(9-4root5)

1/x=1/(9-4root5)

here rationalising factor = (9+4root5)

multiplying numerator and denominator with rationalising factor we get,

1×(9+4root5)/(9-4root5)×(9+4root5)

(9+4root5)/(9²-(4root5)²)

=(9-4root5)/81-80

=(9+4root5)/1

therefore 1/x = (9=4root5)

x+1/x = (9+4root5)

x+1/x=9-4root5+9=4root5....................eq.1

=9+9

=18

squaring both sides,

(x+1/x)²=18²

(x+1/x)²=x²+(1/x)²+2×x×1/x

x²+1/x²+2=324

x²+1/x²=324-2=322

Hope it helps