Step 1: Let's analyze the given number pairs:
- In Option (A), (B), and (D), the digits of both numbers are simply reversed (e.g., 123 and 321, 456 and 654, 678 and 876).
- However, in option (C), the digits of 789 and 978 are not simply reversed, as 789 → 978 involves a change in the order of digits.
Thus, the odd pair is 789 - 978, as the digits are rearranged in a way that does not follow the simple reverse pattern.
Thus, the correct answer is option (C) 789 - 978.
If the roots of the quadratic equation \( ax^2 + bx + c = 0 \) are real and equal, then: