The tutor above interpreted the problem wrong.  He interpreted it as if it had read:
The sum of three consecutive even numbers is the same as THE SUM OF (twice the
difference of the smallest TWO numberS) and 14.
But it's this:
The sum of three consecutive even numbers is the same as twice the difference
of the smallest number and 14
Instead of doing yours for you, I'll do this one instead which is
done exactly the same:
The sum of four consecutive even numbers is the same as three times the
difference of the next to the smallest number and 20.
x = the smallest
x+2 = next to smallest
x+4 = next to largest
x+6 = largest
The sum of four consecutive even numbers 
So we add them all up by putting in plusses 
x + (x+2) + (x+4) + (x+6)
is the same as 
That means to put an equal sign after it.
So we have:
x + (x+2) + (x+4) + (x+6) =
three times 
So we write 3∙ after the equal sign, and we have:
x + (x+2) + (x+4) + (x+6) = 3∙
the difference of the next to the smallest number and 20. 
That means to subtract them in that order.  Since the next to the smallest is
(x+2) is mentioned first and 20 second, we subtract them in that order and put
[(x+2)-20] after the 3∙
So the equation is
x + (x+2) + (x+4) + (x+6) = 3∙[(x+2)-20]
x + x + 2 + x + 4 + x + 6 = 3∙[x + 2 - 20]
4x + 12 = 3∙[x - 18]
4x + 12 = 3x - 54
      x = -66
  x = the smallest = -66
x+2 = next to smallest = -66+2 = -64
x+4 = next to largest = -66+4 = -62
x+6 = largest = -66+6 = -60
Now do yours, which has only 3 consecutive numbers.
[Your answers will be negative too]
Edwin