Answer:
The answer to this question is 12x.
[tex]\huge\boxed{\sf 12x}[/tex]
Step-by-step explanation:
[tex]\sf 5x+7x\\\\Take \ x \ as \ common\\\\x(5+7)\\\\x(12)\\\\= 12x\\\\\rule[225]{225}{2}[/tex]
Hope this helped!
~AH1807