_2_quest_4() {
    var xy1 = solve_2(system_2_eq_1[0], system_2_eq_1[1], system_2_eq_1[2], system_2_eq_2[0], system_2_eq_2[1], system_2_eq_2[2]);
    var xy2 = solve_2(system_2_eq_2[0], system_2_eq_2[1], system_2_eq_2[2], system_2_eq_3[0], system_2_eq_3[1], system_2_eq_3[2]);
    var xy3 = solve_2(system_2_eq_3[0], system_2_eq_3[1], system_2_eq_3[2], system_2_eq_1[0], system_2_eq_1[1], system_2_eq_1[2]);    
    if(Math.abs(xy1[0] - xy2[0]) > 0.1 || 
       Math.abs(xy1[1] - xy2[1]) > 0.1){
        document