The value of the discriminant of the equation 2x² - 3x + 5 = 0, is:

1. 31

2. $\sqrt{-31}$

3. $\sqrt{31}$

4. -31

If the equation, ax² + 2x + a = 0 has two real and equal roots, then:

1. a = 0, 1

2. a = 1, 1

3. a = 0, -1

4. a = -1, 1

The value of the discriminant of the equation, x² - ($\sqrt{2}$ + 1)x + $\sqrt{2}$ = 0 is:

1. 3 + $2\sqrt{2}$

2. 1 - $2\sqrt{2}$

3. 3 - $2\sqrt{2}$

4. 2 - $\sqrt{2}$

The roots of the equation $x + \dfrac{1}{x}$ = 3 are:

1. $\dfrac{2 \pm \sqrt{5}}{2}$

2. $\dfrac{3 \pm \sqrt{5}}{2}$

3. $\dfrac{1 \pm \sqrt{3}}{2}$

4. none of these