Question

12x - 4  +  x = 9

Answer 1

12x-4+x=9
12x+x=9+4
13x=13
x=13/13
x=1

Agora eu espero ter ajudado

Answer 2

12x -4 +x=9
12x +x= 9 +4
13x= 13
x= 13/13
x= 1