If $x + \dfrac{1}{x} = 2, \text{ then } x^2 + \dfrac{1}{x^2}$ is equal to

1. 4

2. 2

3. 0

4. none of these

We know that,

$x^2 + \dfrac{1}{x^2} = \Big(x + \dfrac{1}{x}\Big)^2 -2$.

Substituting values we get,

$x^2 + \dfrac{1}{x^2} = (2)^2 - 2 = 4 - 2 = 2$.

Hence, Option 2 is the correct option.