Question

Three consecutive integers have a sum of –21. Which equation can be used to find the value of the three numbers?

x+x+x=-21
x+2x+3x=-21
x+(x+1)+(x+2)=-21
x+(x+2)+(x+4)=-21

Answer 1

The third one, x+(x+1)+(x+2)=-21 because x, x+1 and x+2 are three consecutive numbers.