Prime numbers Rules

GRE Quant Problem Solving
1

In a question about prime number that can be the sum of two perfect squares, the solutions said: Prime numbers that are 11 greater than a multiple of 44 can always be written as the sum of two squares. And prime numbers that are 33 greater than a multiple of 44 can never be written as the sum of two squares.

why is that?

2

Where did you see this?

3

This is the question: Which of the following prime numbers can be written as the sum of two perfect squares?

4

Did you recently ask this question to our customer service representatives?