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