Whakaoti i te 3x^2+6x=8

$$3 x ^ { 2 } + 6 x = 8$$

Whakaoti mō x

$$x=\frac{\sqrt{33}}{3}-1\approx 0.914854216$$

$$x=-\frac{\sqrt{33}}{3}-1\approx -2.914854216$$

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.

$$3x^{2}+6x=8$$

Me tango 8 mai i ngā taha e rua o te whārite.

$$3x^{2}+6x-8=8-8$$

Mā te tango i te 8 i a ia ake anō ka toe ko te 0.

$$3x^{2}+6x-8=0$$

Kei te āhua arowhānui tēnei whārite: ax^{2}+bx+c=0. Me whakakapi 3 mō a, 6 mō b, me -8 mō c i te tikanga tātai pūrua, \frac{-b±\sqrt{b^{2}-4ac}}{2a}.

$$x=\frac{-6±\sqrt{6^{2}-4\times 3\left(-8\right)}}{2\times 3}$$

Pūrua 6.

$$x=\frac{-6±\sqrt{36-4\times 3\left(-8\right)}}{2\times 3}$$

Whakareatia -4 ki te 3.

$$x=\frac{-6±\sqrt{36-12\left(-8\right)}}{2\times 3}$$

Whakareatia -12 ki te -8.

$$x=\frac{-6±\sqrt{36+96}}{2\times 3}$$

Tāpiri 36 ki te 96.

$$x=\frac{-6±\sqrt{132}}{2\times 3}$$

Tuhia te pūtakerua o te 132.

$$x=\frac{-6±2\sqrt{33}}{2\times 3}$$

Whakareatia 2 ki te 3.

$$x=\frac{-6±2\sqrt{33}}{6}$$

Nā, me whakaoti te whārite x=\frac{-6±2\sqrt{33}}{6} ina he tāpiri te ±. Tāpiri -6 ki te 2\sqrt{33}.

$$x=\frac{2\sqrt{33}-6}{6}$$

Whakawehe -6+2\sqrt{33} ki te 6.

$$x=\frac{\sqrt{33}}{3}-1$$

Nā, me whakaoti te whārite x=\frac{-6±2\sqrt{33}}{6} ina he tango te ±. Tango 2\sqrt{33} mai i -6.

$$x=\frac{-2\sqrt{33}-6}{6}$$

Whakawehe -6-2\sqrt{33} ki te 6.

$$x=-\frac{\sqrt{33}}{3}-1$$

Kua oti te whārite te whakatau.

$$x=\frac{\sqrt{33}}{3}-1 x=-\frac{\sqrt{33}}{3}-1$$

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.

$$3x^{2}+6x=8$$

Whakawehea ngā taha e rua ki te 3.

$$\frac{3x^{2}+6x}{3}=\frac{8}{3}$$

Mā te whakawehe ki te 3 ka wetekia te whakareanga ki te 3.

$$x^{2}+\frac{6}{3}x=\frac{8}{3}$$

Whakawehe 6 ki te 3.

$$x^{2}+2x=\frac{8}{3}$$

Whakawehea te 2, te tau whakarea o te kīanga tau x, ki te 2 kia riro ai te 1. Nā, tāpiria te pūrua o te 1 ki ngā taha e rua o te whārite. Mā konei e pūrua tika tonu ai te taha mauī o te whārite.

$$x^{2}+2x+1^{2}=\frac{8}{3}+1^{2}$$

Pūrua 1.

$$x^{2}+2x+1=\frac{8}{3}+1$$

Tāpiri \frac{8}{3} ki te 1.

$$x^{2}+2x+1=\frac{11}{3}$$

Tauwehea x^{2}+2x+1. 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}.

$$\left(x+1\right)^{2}=\frac{11}{3}$$

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

$$\sqrt{\left(x+1\right)^{2}}=\sqrt{\frac{11}{3}}$$

Whakarūnātia.

$$x+1=\frac{\sqrt{33}}{3} x+1=-\frac{\sqrt{33}}{3}$$

Me tango 1 mai i ngā taha e rua o te whārite.

$$x=\frac{\sqrt{33}}{3}-1 x=-\frac{\sqrt{33}}{3}-1$$