Question

If $x ^ 2 + 1 / x ^ 2 = 98$ find the value of $x + 1 / x$

• A. 12
• B. 11
• C. 10
• D. 9

Answer 1

Answer:

C. 10

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

$(x+1/x)^2=98+2$

$(x+1/x)^2=100$

$x+1/x=\sqrt{100}=10$