Respuesta :

n in (-oo:+oo)

-13 = n-8 // - n-8

8-n-13 = 0

-n-5 = 0 // + 5

-n = 5 // * -1

n = -5

n = -5
You just need to add the 8 to both sides in order to cancel is out, and then you'll get the answer.

13=n-8
n-8+8= n
13+8 =21
n=21