(14xx+1)−(9x−30x−4)<0=(14x(x−4)−(9x−30)(x+1)(x+1)(x−4))<0=(14x2−56−(9x2+9x−30x−30)(x+1)(x−4))<0=(14x2−56−9x2+21x+30(x+1)(x−4))<0=(5x2+21x−26(x+1)(x−4))<05x2+21x−26
will be always greater than zero (as D < 0)∴x∈(−1,4)