En voici une autre : \documentclass[10pt]{article} % \usepackage[utf8]{inputenc} % \usepackage[T1]{fontenc} % \usepackage{lmodern} \usepackage[french]{babel} \usepackage[a4paper,left=20mm,right=20mm,top=15mm,bottom=15mm]{geometry} \usepackage{amssymb} \usepackage{amsmath} \DecimalMathComma % pour les virgules dans les nombres \begin{document} \begin{tabular}{ccccc} \begin{minipage}[t]{0.20\linewidth} $\left\{ \begin{array}{lll} \alpha_{1}-\alpha_{2}-\alpha_{3}=0\\ \alpha_{1}-\alpha_{3}=0\\ \alpha_{1}+\alpha_{2}=0\\ \end{array} \right.$ \end{minipage} & \begin{minipage}[t]{0.10\linewidth} $\implies$ \end{minipage} & \begin{minipage}[t]{0.20\linewidth} $\left\{ \begin{array}{ll} \alpha_{1}-\alpha_{2}-\alpha_{3}=0\\ \alpha_{1}=-\alpha_{2}\\ \alpha_{1}=\alpha_{3}\\ \end{array} \right.$ \end{minipage} & \begin{minipage}[t]{0.10\linewidth} $\implies$ \end{minipage} & \begin{minipage}[t]{0.20\linewidth} $\left\{ \begin{array}{ll} \alpha_{1}=0\\ \alpha_{2}=0\\ \alpha_{3}=0\\ \end{array} \right.$ \end{minipage} \end{tabular} \end{document}

En voici une autre : \documentclass[10pt]{article} % \usepackage[utf8]{inputenc} % \usepackage[T1]{fontenc} % \usepackage{lmodern} \usepackage[french]{babel} \usepackage[a4paper,left=20mm,right=20mm,top=15mm,bottom=15mm]{geometry} \usepackage{amssymb} \usepackage{amsmath} \DecimalMathComma % pour les virgules dans les nombres \begin{document} \begin{tabular}{ccccc} \begin{minipage}[t]{0.20\linewidth} $\left\{ \begin{array}{lll} \alpha_{1}-\alpha_{2}-\alpha_{3}=0\\ \alpha_{1}-\alpha_{3}=0\\ \alpha_{1}+\alpha_{2}=0\\ \end{array} \right.$ \end{minipage} & \begin{minipage}[t]{0.10\linewidth} $\implies$ \end{minipage} & \begin{minipage}[t]{0.20\linewidth} $\left\{ \begin{array}{ll} \alpha_{1}-\alpha_{2}-\alpha_{3}=0\\ \alpha_{1}=-\alpha_{2}\\ \alpha_{1}=\alpha_{3}\\ \end{array} \right.$ \end{minipage} & \begin{minipage}[t]{0.10\linewidth} $\implies$ \end{minipage} & \begin{minipage}[t]{0.20\linewidth} $\left\{ \begin{array}{ll} \alpha_{1}=0\\ \alpha_{2}=0\\ \alpha_{3}=0\\ \end{array} \right.$ \end{minipage} \end{tabular} \end{document}