Hi there! The answer is A.
[tex]5x + 48 + 7x = 12(x + 4)[/tex]
Work out parenthesis.
[tex]5x + 48 + 7x = 12x + 48[/tex]
Collect terms
[tex]12x + 48 = 12x + 48[/tex]
Now we can see that both sides of the equation are exactly the same. Therefore, it doesn't matter whatever value of x you plug into the equation. Each value of x you plug into the equation makes the equation correct, because both sides are the same (both sides have the same outcome value).
The answer is A.
