Hey!
First, let's solve n
[tex] 10 = 1 + n [/tex]
Switch the equation around:
[tex] 1 + n = 10 [/tex]
Switch it again:
[tex] 10 - 1 = n [/tex]
The sign changes when switched to the other side. At first, it was (+), and now it's (-).
[tex] 10 - 1 = 9 [/tex]
[tex] \framebox{n = 9} [/tex]
Here is a graph:
