() {
    set_system_3();
    draw_plot_named('system_3', 0, 0, false);
    update_system('system_3');
}


//////
/// solver

// lines
var solver_1_eqs = 2;
var solver_1_eq_1;
var solver_1_eq_2;

// start
var start_x;
var start_y;

// margin
var end_step_length;

// current id
var solver_1_eq_temp_id = 1;

// temps
var solver_1_eq_1_temp;
var solver_1_eq_2_temp;
var end_step_length_temp;

function set_solver_1() {
    solver_1_eq_1 = [-0.9, 1.0, -1.0]
    solver_1_eq_2 = [-0.15, 1.0, 2.5]
    start_x = 1.0;
