If twice the opposite of a number is increased by 5, the result is the opposite of the number. What is the #?

Question

I found this problem in the book Saxon Algebra 2 Third Edition and am baffled by the wording. I've attempted to comprehend it but it seems impossible. Any ideas?

Answer 1

Let the number be x; then the opposite is -x.
So we are saying 2(-x) + 5 = -x
and hence 5 = -x + 2x = x.
So the number is 5.

Another way to think about it would be to let y be the opposite of the number. Then the problem says "If twice (y) is increased by 5, the result is (y)", i.e. 2y + 5 = y and hence y = -5. So the original number is the opposite of y, i.e. 5.

Answer 2

2(-n) + 5 = -n

-2n + 5 = -n
-5 +n
-n = -5
n=5