Question

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

a. x+x+x= -21
b. x+2x+3x= -21
c. x+(x+1)+(x+2)= -21
d. x+(x+2)+(x+4)= -21

Answer 1

c. x+(x+1)+(x+2)= -21

Explanation:

Consecutive integers are in a row, like 1,2,3

Let x =the first integer

The next integer is 1 ahead of it

x+1 = next integer

Add 1 to move to the 3rd integer

x+1+1 = x+2

x+2 = the 3rd integer

Add the 3 integers

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