Answer
No solution.
Work Step by Step
Using the properties of equality, the solution to the given equation, $
3(x+4)=3(x-1)
$, is
\begin{array}{l}
3x+12=3x-3
\\\\
3x-3x=-3-12
\\\\
0=-15
\text{ (FALSE)}
.\end{array}
Since the solution above ended with a FALSE statement, then the given equation is a contradiction.
