21.
A triangle with vertices A(1,2), B(3,4), and C(2,1) is transformed by matrix \(M = \begin{pmatrix}2 & 0\\0 & 3\end{pmatrix}\) followed by matrix \(N = \begin{pmatrix}1 & 2\\3 & 4\end{pmatrix}\). Find the coordinates of the image of the triangle after the combined transformation.