The sum of a number and its multiplicative inverse is $6$. Consider: Which of the following is correct?

1. $x + \dfrac{1}{x} = 6$
2. $x^2 + 1 = 6x$
3. $x^2 - 6x - 1 = 0$

• ai and ii
• bi and iii
• cii and iii
• di, ii and iii