Answer by JKismyhusbandbae:
[tex]x-12+4=100\\\mathrm{Add/Subtract\:the\:numbers:}\:-12+4=-8\\x-8=100\\\mathrm{Add\:}8\mathrm{\:to\:both\:sides}\\x-8+8=100+8\\\mathrm{Simplify}\\x=108[/tex]
