\( \definecolor{colordef}{RGB}{249,49,84} \definecolor{colorprop}{RGB}{18,102,241} \)
For any two matrices \(\mathbf{A}\) and \(\mathbf{B}\) of the same size, simplify the expression \(3(\mathbf{A}+\mathbf{B}) - 3\mathbf{A}\).
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