Answer:
[tex]4(3 + x) + x = x + 4[/tex]
[tex]12 + 4x + x = x + 4[/tex]
[tex]12 + 5x = x + 4[/tex]
[tex]5x - x = 4 - 12[/tex]
[tex]4x = - 8[/tex]
[tex] \large \: x = \frac{ - 8}{4} [/tex]
[tex]x = - 2[/tex]
