3.4. Find the sum of all two-digit numbers for each of which the sum of the squares of the digits is 31 more than the product of the same digits.
Solution. Such two-digit numbers are $16, 56, 61, 65$. Their sum is 198.

Answer: 198. (B)

![](https://cdn.mathpix.com/cropped/2024_05_06_a8c31eb257d724803ce6g-04.jpg?height=67&width=815&top_left_y=1003&top_left_x=672)