Question

the sum of three consecutive even number is 30 find the other

Answer 1

make an equation x + (x+2) +(x + 4) = 30. 
Then by combining like items, you get 3x + 6 = 30. 
 Then solve, 3x = 30 - 6;
then 3x = 24,
and x = 8. 
So the 3 numbers are 8, 10 and 12. 

Answer 2

Let the three consecutive even numbers be 2x,2x+2,2x+4.

Given that the sum of three consecutive even numbers = 30.

2x + 2x + 2 + 2x + 4 = 30

6x + 6 = 30

6x = 30 - 6

6x = 24

x = 4

Then 2x = 2 * 4

               = 8


         2x + 2 = 2(4) + 2

                    = 8 + 2

                    = 10 


         2x + 4 = 2(4) + 4

                    = 8 + 4

                    = 12.


Therefore the numbers are 8,10,12.


Verificaition:

2x + 2x + 2 + 2x + 4 = 30

2(4) + 2(4) + 2 + 2(4) + 4 = 30

8 + 8 + 2 + 8 + 4 = 30

30 = 30.


Hope this helps!