y_quest_9").innerHTML = "No, not really. Have you missed the for loop in the solver itself?";
    }else if(document.getElementById("aq8_3").checked) {
        document.getElementById("reply_quest_9").innerHTML = "Exactly! It has 4 nested loops that depend on the number of equations, so the complexity is <i>O(n<sup>4</sup>)</i>.";
        document.getElementById("complexity_buttons").style.display = 'none';
        document.getElementById("buttons_quest_9").style.display = 'none';
        quests[8] = 1;
    