\begin{flalign*} &(c) \quad \text{Rješite sustav jednadžbi za } x, y, \text{ i } z: \\ & \quad \begin{cases} 2x + y §§V4(1,5,1)§§ + z = §§V1(7,21,3)§§ \\ x - 3y + 2z = §§V5(4,12,1)§§ \\ §§V2(1,5,1)§§ x + 2y - z = §§V2(1,4,1)§§ \end{cases} \\ \end{flalign*} </counter>