For x = 5 and y = 3, the value of x² + y² - 2xy + 7 is :

1. 11

2. 169

3. 71

4. 1

If $x + \dfrac{1}{x} = 2$, the value of $x^2 + \dfrac{1}{x^2} + 5$ is :

1. -1

2. 2

3. 9

4. 7

If $x - \dfrac{1}{x} = 8$, the value of $x^2 + \dfrac{1}{x^2} - 8$ is :

1. 56

2. 58

3. 70

4. -4

If $x^2 + \dfrac{1}{x^2} = 9$, the value of $x^4 + \dfrac{1}{x^4} + 5$ is :

1. 78

2. 86

3. 84

4. 81