(9+4√5)² - (9-4√5)²
Answers
Answered by
3
X=9-4√5
∴, 1/x=1/(9-4√5)
=(9+4√5)/(9-4√5)(9+4√5)
=(9+4√5)/{(9)²-(4√5)²}
=(9+4√5)/(81-80)
=9+4√5
∴, x²-1/x²
=(x+1/x)(x-1/x)
=(9-4√5+9+4√5)(9-4√5-9-4√5)
=(18)(-8√5)
=-144√5
x³+1/x³
=(x+1/x)³-3·x·1/x(x+1/x)
=(9-4√5+9+4√5)³-3(9-4√5+9+4√5)
=(9)³-3(9)
=729-27
=702
Hope this helps you.
Please mark as brainliest answer.
Answered by
1
Answer:
X=9-4√5
∴, 1/x=1/(9-4√5)
=(9+4√5)/(9-4√5)(9+4√5)
=(9+4√5)/{(9)²-(4√5)²}
=(9+4√5)/(81-80)
=9+4√5
∴, x²-1/x²
=(x+1/x)(x-1/x)
=(9-4√5+9+4√5)(9-4√5-9-4√5)
=(18)(-8√5)
=-144√5
x³+1/x³
=(x+1/x)³-3·x·1/x(x+1/x)
=(9-4√5+9+4√5)³-3(9-4√5+9+4√5)
=(9)³-3(9)
=729-27
=702
Hope this helps ❤️
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