Question

If $x^2+1/x^2=66$ find$x-1/x$

• A. 10
• B. 9
• C. 8
• D. 6

Answer 1

Answer:

C. 8

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

$(x-1/x)^2=x^2+1/x^2-2=66-2=64$

$x-1/x=\sqrt{64}=8$