Whenever three consecutive integers already together, the sun is always equal to three times the middle number. for example 7+8+9 = 3(8) and negative for plus -3+92 = 3(-3)

Let 'n' be an integer, then 3 consecutive integers added together can be written as: (n-1) + (n) + (n+1) , if we take off the brackets we get n-1+n+n+1 which simplifies to 3n. this is why 3 consecutive integers add up to 3 times the middle number!

hope this helps!