For equation $\dfrac{1}{x} + \dfrac{1}{x - 5} = \dfrac{3}{10}$; one value of x is :

1. $-\dfrac{5}{3}$

2. 10

3. -10

4. 5

Which of the following is correct for the equation $\dfrac{1}{x - 3} - \dfrac{1}{x + 5}$ = 1 ?

1. x ≠ 3 and x = -5

2. x = 3 and x ≠ -5

3. x ≠ 3 and x ≠ -5

4. x > 3 and x < 5

Solve :

2x⁴ - 5x² + 3 = 0

Solve :

x⁴ - 2x² - 3 = 0