For this case we must find the value of the variable "x" of the following equation:
[tex]12 = x + 3[/tex]
So, we follow the steps:
Subtracting 3 from both sides of the equation we have:
[tex]12-3=x+3-3[/tex]
Different signs are subtracted and the sign of the major is placed:
[tex]9 = x\\x = 9[/tex]
Thus, the value of x is 9.
Answer:
[tex]x = 9[/tex]