Assertion (A): If $x^2 - 2x - 1 = 0$, then $x^2 + \dfrac{1}{x^2} = 6$.
Reason (R): x² - 2x - 1 can be written as (x - 1)².

1. A is true, R is false

2. A is false, R is true

3. Both A and R are true

4. Both A and R are false

Assertion (A): (1 - 3x)³ can be expanded as 1 - 27x³ - 9x - 27x².
Reason (R): (a - b)³ = a³ - b³ - 3ab(a - b)

1. A is true, R is false

2. A is false, R is true

3. Both A and R are true

4. Both A and R are false

If x + y = −4, the value of x³ + y³ − 12xy + 64 is :

1. 1

2. -1

3. 4

4. 0

If a + b + c = 0, then $\dfrac{(a + b)^2}{ab} + \dfrac{(b + c)^2}{bc} + \dfrac{(c + a)^2}{ac}$ is equal to :

1. 0

2. 1

3. 3

4. abc