Let's introduce letters. The suitable algebra is: (1) an integer divisible by 3; (2) an integer whose remainder is 2

Let's introduce letters. The suitable algebra is: (1) an integer divisible by 3; (2) an integer whose remainder is 2

3x,3x+2

Try to introduce letters and express them with appropriate algebraic expressions: integers divisible by 3

3N (n is an integer)

Let's know that A.B.C is an integer. If for any integer x, the algebraic formula a multiplied by the square of x plus B multiplied by x plus C is divisible by 3, it is proved that a multiplied by B multiplied by C is divisible by 27
fast
ah

Let x = 0,1, - 1 be substituted
c=3k
a+b+c=3m
a-b+c=3n
We can get that a, B and C are all multiples of 3