Answer :
[tex]5x+48+7x=12(x+4)\\\\12x+48=12x+48\\\\L=R\\\\There\ are\ infinitly\ many\ solutions.[/tex]
5x+48+7x=12(x+4)
12x+48=12x+48
[as they both are like terms, that equals to 0=0]
0=0
HOPE THIS HELPS!!!!!!