đố tính được : X= -\frac{1}{2} \, \sqrt{-{\left(\frac{27 \, eb^{2} + 2 \, c^{3} - 9 \, bcd - 9 \, {\left(8 \, ec - 3 \, d^{2}\right)} a}{54 \, a^{3}} + \frac{\sqrt{-\frac{256}{3} \, e^{3} a^{3} + 9 \, a^{2} d^{4} + \frac{2}{3} \, {\left(2 \, b^{3} - 9 \, abc\right)} d^{3} + \frac{1}{3} \, {\left(27 \, b^{4} - 144 \, ab^{2} c + 128 \, a^{2} c^{2} + 192 \, a^{2} bd\right)} e^{2} - \frac{1}{3} \, {\left(b^{2} c^{2} - 4 \, ac^{3}\right)} d^{2} + \frac{2}{3} \, {\left(2 \, b^{2} c^{3} - 8 \, ac^{4} + 3 \, {\left(ab^{2} - 24 \, a^{2} c\right)} d^{2} - {\left(9 \, b^{3} c - 40 \, abc^{2}\right)} d\right)} e}}{6 \, a^{3}\right)}^{\frac{1}{3}} - \frac{c}{3 \, a} + \frac{b^{2} - 2 \, ac}{2 \, a^{2}} - \frac{12 \, ea + c^{2} - 3 \, bd}{9 \, a^{2} {\left(\frac{27 \, eb^{2} + 2 \, c^{3} - 9 \, bcd - 9 \, {\left(8 \, ec - 3 \, d^{2}\right)} a}{54 \, a^{3}} + \frac{\sqrt{-\frac{256}{3} \, e^{3} a^{3} + 9 \, a^{2} d^{4} + \frac{2}{3} \, {\left(2 \, b^{3} - 9 \, abc\right)} d^{3} + \frac{1}{3} \, {\left(27 \, b^{4} - 144 \, ab^{2} c + 128 \, a^{2} c^{2} + 192 \, a^{2} bd\right)} e^{2} - \frac{1}{3} \, {\left(b^{2} c^{2} - 4 \, ac^{3}\right)} d^{2} + \frac{2}{3} \, {\left(2 \, b^{2} c^{3} - 8 \, ac^{4} + 3 \, {\left(ab^{2} - 24 \, a^{2} c\right)} d^{2} - {\left(9 \, b^{3} c - 40 \, abc^{2}\right)} d\right)} e}}{6 \, a^{3}\right)}^{\frac{1}{3}}} + \frac{3 \, {\left(b^{3} - 4 \, abc + 8 \, a^{2} d\right)}}{2 \, a^{2} \sqrt{\frac{36 \, a^{2} {\left(\frac{27 \, eb^{2} + 2 \, c^{3} - 9 \, bcd - 9 \, {\left(8 \, ec - 3 \, d^{2}\right)} a}{54 \, a^{3}} + \frac{\sqrt{-\frac{256}{3} \, e^{3} a^{3} + 9 \, a^{2} d^{4} + \frac{2}{3} \, {\left(2 \, b^{3} - 9 \, abc\right)} d^{3} + \frac{1}{3} \, {\left(27 \, b^{4} - 144 \, ab^{2} c + 128 \, a^{2} c^{2} + 192 \, a^{2} bd\right)} e^{2} - \frac{1}{3} \, {\left(b^{2} c^{2} - 4 \, ac^{3}\right)} d^{2} + \frac{2}{3} \, {\left(2 \, b^{2} c^{3} - 8 \, ac^{4} + 3 \, {\left(ab^{2} - 24 \, a^{2} c\right)} d^{2} - {\left(9 \, b^{3} c - 40 \, abc^{2}\right)} d\right)} e}}{6 \, a^{3}\right)}^{\frac{2}{3}} + 48 \, ea + 4 \, c^{2} - 12 \, bd + 3 \, {\left(3 \, b^{2} - 8 \, ac\right)} {\left(\frac{27 \, eb^{2} + 2 \, c^{3} - 9 \, bcd - 9 \, {\left(8 \, ec - 3 \, d^{2}\right)} a}{54 \, a^{3}} + \frac{\sqrt{-\frac{256}{3} \, e^{3} a^{3} + 9 \, a^{2} d^{4} + \frac{2}{3} \, {\left(2 \, b^{3} - 9 \, abc\right)} d^{3} + \frac{1}{3} \, {\left(27 \, b^{4} - 144 \, ab^{2} c + 128 \, a^{2} c^{2} + 192 \, a^{2} bd\right)} e^{2} - \frac{1}{3} \, {\left(b^{2} c^{2} - 4 \, ac^{3}\right)} d^{2} + \frac{2}{3} \, {\left(2 \, b^{2} c^{3} - 8 \, ac^{4} + 3 \, {\left(ab^{2} - 24 \, a^{2} c\right)} d^{2} - {\left(9 \, b^{3} c - 40 \, abc^{2}\right)} d\right)} e}}{6 \, a^{3}\right)}^{\frac{1}{3}}}{{\left(\frac{27 \, eb^{2} + 2 \, c^{3} - 9 \, bcd - 9 \, {\left(8 \, ec - 3 \, d^{2}\right)} a}{54 \, a^{3}} + \frac{\sqrt{-\frac{256}{3} \, e^{3} a^{3} + 9 \, a^{2} d^{4} + \frac{2}{3} \, {\left(2 \, b^{3} - 9 \,abc\right)