If x+1/x=3 then x-1/x=?

If x+1/x=3 then x-1/x=?

A √5

B √13

C √7

Solution

Correct Answer: Option A

x+1/x=3
বা, (x+1/x)² =(3)²
বা, (x-1/x)²+4.x.1/x=9
বা, (x-1/x)²+4=9
বা, (x-1/x)²=5
x-1/x=√5