3.4

#include <iostream>

using namespace std;
double a, b;

double function(const double x) {
    return (x + 1) - ((3 * x * x + 4) / x);
}

void input() {
    cout << "Enter a: ";
    cin >> a;

    cout << "Enter b: ";
    cin >> b;
}

int main() {

    input();

    while (b < a) {
        cout << "Input range again:\n";
        input();
    }

    for (double i = a; i <= b; i++) {
        if (i == 0) {
            cout << "\033[1;31mWhen x = 0 there is no solution;\033[0m\n";
        } else {
            cout << "X = " << i << "; Y = " << function(i) << ";\n";
        }
    }
    return 0;
}