Respuesta :
Answer:
[tex]\huge\boxed{\bf\:x = 4}[/tex]
Step-by-step explanation:
[tex]3 + x = 7[/tex]
Bring 3 to the right hand side of the equation and isolate the variable.
[tex]3 + x = 7\\x = 7 - 3\\\boxed{\bf\:x = 4}[/tex]
[tex]\rule{150pt}{2pt}[/tex]