Can we chose the coordinate of the legend_ label
in
g = plot((3/2) - (1/2)*x, (x, 0, 5),thickness=1.5, color="#4b59ea",legend_label='$\\frac{3}{2} - \\frac{1}{2}x$')
g+= plot((11/2) - 2*x, (x, 0, 5),thickness=1.5, color="#e52411",legend_label='$\\frac{11}{2} - 2x$')
g+= plot(-1 + x, (x, 0, 5),thickness=1.5, color="#2ea012",legend_label='$-1 + x$')
g.axes_labels(['$x_1$','$x_2$'])
show(g)