Answer :

To solve the equation [tex]\( 3x + 8 = x - 12 \)[/tex] for [tex]\( x \)[/tex], follow these steps:

1. Move all terms involving [tex]\( x \)[/tex] to one side of the equation:
Subtract [tex]\( x \)[/tex] from both sides to get:
[tex]\[ 3x + 8 - x = x - 12 - x \][/tex]
Simplifying both sides, we get:
[tex]\[ 2x + 8 = -12 \][/tex]

2. Isolate the term involving [tex]\( x \)[/tex]:
Subtract 8 from both sides to get:
[tex]\[ 2x + 8 - 8 = -12 - 8 \][/tex]
Simplifying both sides, we get:
[tex]\[ 2x = -20 \][/tex]

3. Solve for [tex]\( x \)[/tex]:
Divide both sides by 2 to get:
[tex]\[ \frac{2x}{2} = \frac{-20}{2} \][/tex]
Simplifying both sides, we get:
[tex]\[ x = -10 \][/tex]

Thus, the solution for [tex]\( x \)[/tex] is [tex]\(-10\)[/tex].

Therefore, the best answer is:
C. [tex]\(-10\)[/tex]