Whakaoti mō x (complex solution)
x=-3+\sqrt{11}i\approx -3+3.31662479i
x=-\sqrt{11}i-3\approx -3-3.31662479i
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Tohaina
Kua tāruatia ki te papatopenga
2x^{2}+12x+40=0
Ko ngā whārite katoa o te āhua ax^{2}+bx+c=0 ka taea te whakaoti mā te whakamahi i te tikanga tātai pūrua: \frac{-b±\sqrt{b^{2}-4ac}}{2a}. E rua ngā otinga ka puta i te tikanga tātai pūrua, ko tētahi ina he tāpiri a ±, ā, ko tētahi ina he tango.
x=\frac{-12±\sqrt{12^{2}-4\times 2\times 40}}{2\times 2}
Kei te āhua arowhānui tēnei whārite: ax^{2}+bx+c=0. Me whakakapi 2 mō a, 12 mō b, me 40 mō c i te tikanga tātai pūrua, \frac{-b±\sqrt{b^{2}-4ac}}{2a}.
x=\frac{-12±\sqrt{144-4\times 2\times 40}}{2\times 2}
Pūrua 12.
x=\frac{-12±\sqrt{144-8\times 40}}{2\times 2}
Whakareatia -4 ki te 2.
x=\frac{-12±\sqrt{144-320}}{2\times 2}
Whakareatia -8 ki te 40.
x=\frac{-12±\sqrt{-176}}{2\times 2}
Tāpiri 144 ki te -320.
x=\frac{-12±4\sqrt{11}i}{2\times 2}
Tuhia te pūtakerua o te -176.
x=\frac{-12±4\sqrt{11}i}{4}
Whakareatia 2 ki te 2.
x=\frac{-12+4\sqrt{11}i}{4}
Nā, me whakaoti te whārite x=\frac{-12±4\sqrt{11}i}{4} ina he tāpiri te ±. Tāpiri -12 ki te 4i\sqrt{11}.
x=-3+\sqrt{11}i
Whakawehe -12+4i\sqrt{11} ki te 4.
x=\frac{-4\sqrt{11}i-12}{4}
Nā, me whakaoti te whārite x=\frac{-12±4\sqrt{11}i}{4} ina he tango te ±. Tango 4i\sqrt{11} mai i -12.
x=-\sqrt{11}i-3
Whakawehe -12-4i\sqrt{11} ki te 4.
x=-3+\sqrt{11}i x=-\sqrt{11}i-3
Kua oti te whārite te whakatau.
2x^{2}+12x+40=0
Ko ngā whārite pūrua pēnei i tēnei nā ka taea te whakaoti mā te whakaoti i te pūrua. Hei whakaoti i te pūrua, ko te whārite me mātua tuhi ki te āhua x^{2}+bx=c.
2x^{2}+12x+40-40=-40
Me tango 40 mai i ngā taha e rua o te whārite.
2x^{2}+12x=-40
Mā te tango i te 40 i a ia ake anō ka toe ko te 0.
\frac{2x^{2}+12x}{2}=-\frac{40}{2}
Whakawehea ngā taha e rua ki te 2.
x^{2}+\frac{12}{2}x=-\frac{40}{2}
Mā te whakawehe ki te 2 ka wetekia te whakareanga ki te 2.
x^{2}+6x=-\frac{40}{2}
Whakawehe 12 ki te 2.
x^{2}+6x=-20
Whakawehe -40 ki te 2.
x^{2}+6x+3^{2}=-20+3^{2}
Whakawehea te 6, te tau whakarea o te kīanga tau x, ki te 2 kia riro ai te 3. Nā, tāpiria te pūrua o te 3 ki ngā taha e rua o te whārite. Mā konei e pūrua tika tonu ai te taha mauī o te whārite.
x^{2}+6x+9=-20+9
Pūrua 3.
x^{2}+6x+9=-11
Tāpiri -20 ki te 9.
\left(x+3\right)^{2}=-11
Tauwehea x^{2}+6x+9. Ko te tikanga pūnoa, ina ko x^{2}+bx+c he pūrua tika pūrua tika pū, ka taea taua mea te tauwehea i ngā wā katoa hei \left(x+\frac{b}{2}\right)^{2}.
\sqrt{\left(x+3\right)^{2}}=\sqrt{-11}
Tuhia te pūtakerua o ngā taha e rua o te whārite.
x+3=\sqrt{11}i x+3=-\sqrt{11}i
Whakarūnātia.
x=-3+\sqrt{11}i x=-\sqrt{11}i-3
Me tango 3 mai i ngā taha e rua o te whārite.