Whakaoti i te x^2+3x+12=0

$$x ^ { 2 } + 3 x + 12 = 0$$

Whakaoti mō x (complex solution)

$$x=\frac{-3+\sqrt{39}i}{2}\approx -1.5+3.122498999i$$

$$x=\frac{-\sqrt{39}i-3}{2}\approx -1.5-3.122498999i$$

Ngā Upane e Whakamahi ana i te Tikanga Tātai Pūrua

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.

$$x^{2}+3x+12=0$$

Kei te āhua arowhānui tēnei whārite: ax^{2}+bx+c=0. Me whakakapi 1 mō a, 3 mō b, me 12 mō c i te tikanga tātai pūrua, \frac{-b±\sqrt{b^{2}-4ac}}{2a}.

$$x=\frac{-3±\sqrt{3^{2}-4\times 12}}{2}$$

Pūrua 3.

$$x=\frac{-3±\sqrt{9-4\times 12}}{2}$$

Whakareatia -4 ki te 12.

$$x=\frac{-3±\sqrt{9-48}}{2}$$

Tāpiri 9 ki te -48.

$$x=\frac{-3±\sqrt{-39}}{2}$$

Tuhia te pūtakerua o te -39.

$$x=\frac{-3±\sqrt{39}i}{2}$$

Nā, me whakaoti te whārite x=\frac{-3±\sqrt{39}i}{2} ina he tāpiri te ±. Tāpiri -3 ki te i\sqrt{39}.

$$x=\frac{-3+\sqrt{39}i}{2}$$

Nā, me whakaoti te whārite x=\frac{-3±\sqrt{39}i}{2} ina he tango te ±. Tango i\sqrt{39} mai i -3.

$$x=\frac{-\sqrt{39}i-3}{2}$$

Kua oti te whārite te whakatau.

$$x=\frac{-3+\sqrt{39}i}{2} x=\frac{-\sqrt{39}i-3}{2}$$

Ngā Upane mō te Whakaoti i te Pūrua

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.

$$x^{2}+3x+12=0$$

Me tango 12 mai i ngā taha e rua o te whārite.

$$x^{2}+3x+12-12=-12$$

Mā te tango i te 12 i a ia ake anō ka toe ko te 0.

$$x^{2}+3x=-12$$

Whakawehea te 3, te tau whakarea o te kīanga tau x, ki te 2 kia riro ai te \frac{3}{2}. Nā, tāpiria te pūrua o te \frac{3}{2} ki ngā taha e rua o te whārite. Mā konei e pūrua tika tonu ai te taha mauī o te whārite.

$$x^{2}+3x+\left(\frac{3}{2}\right)^{2}=-12+\left(\frac{3}{2}\right)^{2}$$

Pūruatia \frac{3}{2} mā te pūrua i te taurunga me te tauraro o te hautanga.

$$x^{2}+3x+\frac{9}{4}=-12+\frac{9}{4}$$

Tāpiri -12 ki te \frac{9}{4}.

$$x^{2}+3x+\frac{9}{4}=-\frac{39}{4}$$

Tauwehea x^{2}+3x+\frac{9}{4}. 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}.

$$\left(x+\frac{3}{2}\right)^{2}=-\frac{39}{4}$$

Tuhia te pūtakerua o ngā taha e rua o te whārite.

$$\sqrt{\left(x+\frac{3}{2}\right)^{2}}=\sqrt{-\frac{39}{4}}$$

Whakarūnātia.

$$x+\frac{3}{2}=\frac{\sqrt{39}i}{2} x+\frac{3}{2}=-\frac{\sqrt{39}i}{2}$$

Me tango \frac{3}{2} mai i ngā taha e rua o te whārite.

$$x=\frac{-3+\sqrt{39}i}{2} x=\frac{-\sqrt{39}i-3}{2}$$