Se da la desigualdad:
$$x \frac{x^{2} \left(x - 1\right)}{2} + 7 \geq 0$$
Para resolver esta desigualdad primero hay que resolver la ecuación correspondiente:
$$x \frac{x^{2} \left(x - 1\right)}{2} + 7 = 0$$
Resolvemos:
$$x_{1} = \frac{1}{4} - \frac{\sqrt{\frac{1}{4} + \frac{28}{3 \sqrt[3]{\frac{7}{8} + \frac{7 \sqrt{10671} i}{72}}} + 2 \sqrt[3]{\frac{7}{8} + \frac{7 \sqrt{10671} i}{72}}}}{2} - \frac{\sqrt{\frac{1}{2} - 2 \sqrt[3]{\frac{7}{8} + \frac{7 \sqrt{10671} i}{72}} - \frac{1}{4 \sqrt{\frac{1}{4} + \frac{28}{3 \sqrt[3]{\frac{7}{8} + \frac{7 \sqrt{10671} i}{72}}} + 2 \sqrt[3]{\frac{7}{8} + \frac{7 \sqrt{10671} i}{72}}}} - \frac{28}{3 \sqrt[3]{\frac{7}{8} + \frac{7 \sqrt{10671} i}{72}}}}}{2}$$
$$x_{2} = \frac{1}{4} + \frac{\sqrt{\frac{1}{4} + \frac{28}{3 \sqrt[3]{\frac{7}{8} + \frac{7 \sqrt{10671} i}{72}}} + 2 \sqrt[3]{\frac{7}{8} + \frac{7 \sqrt{10671} i}{72}}}}{2} - \frac{\sqrt{\frac{1}{2} - 2 \sqrt[3]{\frac{7}{8} + \frac{7 \sqrt{10671} i}{72}} + \frac{1}{4 \sqrt{\frac{1}{4} + \frac{28}{3 \sqrt[3]{\frac{7}{8} + \frac{7 \sqrt{10671} i}{72}}} + 2 \sqrt[3]{\frac{7}{8} + \frac{7 \sqrt{10671} i}{72}}}} - \frac{28}{3 \sqrt[3]{\frac{7}{8} + \frac{7 \sqrt{10671} i}{72}}}}}{2}$$
$$x_{3} = \frac{1}{4} + \frac{\sqrt{\frac{1}{2} - 2 \sqrt[3]{\frac{7}{8} + \frac{7 \sqrt{10671} i}{72}} - \frac{1}{4 \sqrt{\frac{1}{4} + \frac{28}{3 \sqrt[3]{\frac{7}{8} + \frac{7 \sqrt{10671} i}{72}}} + 2 \sqrt[3]{\frac{7}{8} + \frac{7 \sqrt{10671} i}{72}}}} - \frac{28}{3 \sqrt[3]{\frac{7}{8} + \frac{7 \sqrt{10671} i}{72}}}}}{2} - \frac{\sqrt{\frac{1}{4} + \frac{28}{3 \sqrt[3]{\frac{7}{8} + \frac{7 \sqrt{10671} i}{72}}} + 2 \sqrt[3]{\frac{7}{8} + \frac{7 \sqrt{10671} i}{72}}}}{2}$$
$$x_{4} = \frac{1}{4} + \frac{\sqrt{\frac{1}{2} - 2 \sqrt[3]{\frac{7}{8} + \frac{7 \sqrt{10671} i}{72}} + \frac{1}{4 \sqrt{\frac{1}{4} + \frac{28}{3 \sqrt[3]{\frac{7}{8} + \frac{7 \sqrt{10671} i}{72}}} + 2 \sqrt[3]{\frac{7}{8} + \frac{7 \sqrt{10671} i}{72}}}} - \frac{28}{3 \sqrt[3]{\frac{7}{8} + \frac{7 \sqrt{10671} i}{72}}}}}{2} + \frac{\sqrt{\frac{1}{4} + \frac{28}{3 \sqrt[3]{\frac{7}{8} + \frac{7 \sqrt{10671} i}{72}}} + 2 \sqrt[3]{\frac{7}{8} + \frac{7 \sqrt{10671} i}{72}}}}{2}$$
Descartamos las soluciones complejas:
Esta ecuación no tiene soluciones,
significa que esta desigualdad se cumple siempre o no se cumple nunca
comprobemos
sustituimos con un punto arbitrario, por ejemplo
x0 = 0
$$0 \frac{\left(-1\right) 0^{2}}{2} + 7 \geq 0$$
7 >= 0
signo desigualdades se cumple cuando