Jon P. answered 02/28/15
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First assign a variable to the number. Call it x.
Now follow exactly what the problem says:
"twice the difference of a number and 2" -- that's 2 (x - 2) (though that's ambiguous -- see below)
"is equal to" -- in other words, =
"three times the sum of the number and 4" -- 3 (x + 4)
So there's an equation, which can be solved easily:
2 (x - 2) = 3 (x + 4)
2x - 4 = 3x + 12
2x = 3x + 16
-x = 16
x = -16
HOWEVER... Maybe "the difference of a number and 2" means 2 - x, and not x - 2. What happens then?
2 (2 - x) = 3 (x + 4)
4 - 2x = 3x + 12
-8 - 2x = 3x
-8 = 5x
In this case the answer would be -8/5, which is probably not what they wanted.