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If x + 1/x = 5 then x^2 + 1/x^2 = ??

0 votes
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If
x + 1/x = 5
then
x^2 + 1/x^2 = ??

posted Aug 7, 2015 by anonymous

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Same question but 2(x²-1/x²)value pls

2 Answers

+4 votes

x+1/x=5
sqr both side
(x+1/x)^2=5^2
x^2+1/x^2+2=25
so answer is 23

answer Aug 7, 2015 by Vikram Singh
–1 vote

The question gives you x+(1/x)=5 and it is asking for x^2+(1/x^2)
well, remember (a+b)^2=a^2+2ab+b^2
Let's square the question given, that gives you x^2+2*x*(1/x)+(1/x^2)=25
since 2*x*(1/x)=2,then
x^2+(1/x^2)=25-2=23

answer Feb 21, 2018 by anonymous



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