If x^2 + 1/x^2 = 27. Then find x-1/x ?

If x^2 + 1/x^2 = 27. Then find x-1/x

2 Answers
Sahar Mulla ❤
Jan 27, 2018

x-1/x = +-5

Explanation:

just expand, rearrange n substitute,!
(x-1/x)^2

=x^2 -2*x*1/x +(1/x)^2

=x^2 -2+(1/x)^2

=x^2+1/x^2-2

since we have the value of x^2+1/x^2 as 27,

=27-2

=25

=>(x-1/x)^2 = 25

=>x-1/x = +-5

-Sahar

Jim G.
Jan 27, 2018

x-1/x=+-5

Explanation:

"note that "(x-1/x)^2=x^2-2+1/x^2

rArrx^2-2+1/x^2=27-2=25

rArr(x-1/x)^2=25

color(blue)"take the square root of both sides"

rArrx-1/x=+-5larrcolor(blue)"note plus or minus"

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