Question

If $x ^ 2 + 1 / x ^ 2 = 7$ find the value of $x + 1 / x$

• A. 6
• B. 4
• C. 5
• D. 3

Answer 1

Answer:

D. 3

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

$(x+1/x)^2=7+2$

$(x+1/x)^2=9$

$x+1/x=\sqrt{9}=3$