Verified Answer :

\(6(4-x) + 6x = 24\)

First, you develop, and you get:
\(24 - 6x + 6x = 24\)

Then, you put known numbers apart (numbers without x), and unknown numbers apart (numbers with x), and remember that moving from a part to another change the sign of the number. So you get:
\(-6x + 6x = 24-24\)

And now you operate, and u get:
\(0 = 0\)

Since we get the same number in the 2 parts ( the number 0), that means that the correct answer is A (all real numbers)

Hope this Helps! :)