Question 1164055: The sum of twice a number and 3 less than the number is the same as the difference between -19 and the number . What is the number ? Found 3 solutions by josgarithmetic, ikleyn, greenestamps:Answer by josgarithmetic(39620) (Show Source):
the number: n
twice the number: 2n
3 less than the number: n-3
the sum of (twice the number) and (3 less than the number): (2n)+(n-3)
the difference between -19 and the number: -19-n
So
Solve using basic algebra.
A comment about the response from one of the other tutors....
In everyday language, the difference between two numbers is nearly always interpreted as being a positive number. So the difference between 5 and 10 is 5, and the difference between 10 and 5 is 5.
However, in formal mathematics, the difference between A and B is ALWAYS A-B. So the difference between 5 and 10 is 5-10 = -5, and the difference between 10 and 5 is 10-5 = 5.
So in your problem "the difference between -19 and the number" is -19-n -- NOT n-(-19) = n+19.