If $\dfrac{2 + \sqrt{5}}{2 - \sqrt{5}} = x \text{ and } \dfrac{2 - \sqrt{5}}{2 + \sqrt{5}} = y$; find the value of x² - y².

Since 90 = 2 x 3 x 3 x 5, $\dfrac{23}{90}$ is not a terminating decimal;

1. True

2. False

3. none of these

If x = 7 - $\sqrt{5}$, then $x - \dfrac{1}{x}$ is equal to:

1. 14

2. 7

3. $2\sqrt{5}$

4. $\dfrac{301 - 45\sqrt{5}}{44}$

$\dfrac{2 + \sqrt{3}}{2 - \sqrt{3}} - \dfrac{2 - \sqrt{3}}{2 + \sqrt{3}}$ is equal to:

1. 4

2. $2\sqrt{3}$

3. 1

4. $8\sqrt{3}$