Whakaoti i te 3x^2+16x-5=0

$$3 x ^ { 2 } + 16 x - 5 = 0$$

Whakaoti mō x

$$x=\frac{\sqrt{79}-8}{3}\approx 0.296064806$$

$$x=\frac{-\sqrt{79}-8}{3}\approx -5.629398139$$

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.

$$3x^{2}+16x-5=0$$

Kei te āhua arowhānui tēnei whārite: ax^{2}+bx+c=0. Me whakakapi 3 mō a, 16 mō b, me -5 mō c i te tikanga tātai pūrua, \frac{-b±\sqrt{b^{2}-4ac}}{2a}.

$$x=\frac{-16±\sqrt{16^{2}-4\times 3\left(-5\right)}}{2\times 3}$$

Pūrua 16.

$$x=\frac{-16±\sqrt{256-4\times 3\left(-5\right)}}{2\times 3}$$

Whakareatia -4 ki te 3.

$$x=\frac{-16±\sqrt{256-12\left(-5\right)}}{2\times 3}$$

Whakareatia -12 ki te -5.

$$x=\frac{-16±\sqrt{256+60}}{2\times 3}$$

Tāpiri 256 ki te 60.

$$x=\frac{-16±\sqrt{316}}{2\times 3}$$

Tuhia te pūtakerua o te 316.

$$x=\frac{-16±2\sqrt{79}}{2\times 3}$$

Whakareatia 2 ki te 3.

$$x=\frac{-16±2\sqrt{79}}{6}$$

Nā, me whakaoti te whārite x=\frac{-16±2\sqrt{79}}{6} ina he tāpiri te ±. Tāpiri -16 ki te 2\sqrt{79}.

$$x=\frac{2\sqrt{79}-16}{6}$$

Whakawehe -16+2\sqrt{79} ki te 6.

$$x=\frac{\sqrt{79}-8}{3}$$

Nā, me whakaoti te whārite x=\frac{-16±2\sqrt{79}}{6} ina he tango te ±. Tango 2\sqrt{79} mai i -16.

$$x=\frac{-2\sqrt{79}-16}{6}$$

Whakawehe -16-2\sqrt{79} ki te 6.

$$x=\frac{-\sqrt{79}-8}{3}$$

Kua oti te whārite te whakatau.

$$x=\frac{\sqrt{79}-8}{3} x=\frac{-\sqrt{79}-8}{3}$$

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.

$$3x^{2}+16x-5=0$$

Me tāpiri 5 ki ngā taha e rua o te whārite.

$$3x^{2}+16x-5-\left(-5\right)=-\left(-5\right)$$

Mā te tango i te -5 i a ia ake anō ka toe ko te 0.

$$3x^{2}+16x=-\left(-5\right)$$

Tango -5 mai i 0.

$$3x^{2}+16x=5$$

Whakawehea ngā taha e rua ki te 3.

$$\frac{3x^{2}+16x}{3}=\frac{5}{3}$$

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

$$x^{2}+\frac{16}{3}x=\frac{5}{3}$$

Whakawehea te \frac{16}{3}, te tau whakarea o te kīanga tau x, ki te 2 kia riro ai te \frac{8}{3}. Nā, tāpiria te pūrua o te \frac{8}{3} ki ngā taha e rua o te whārite. Mā konei e pūrua tika tonu ai te taha mauī o te whārite.

$$x^{2}+\frac{16}{3}x+\left(\frac{8}{3}\right)^{2}=\frac{5}{3}+\left(\frac{8}{3}\right)^{2}$$

Pūruatia \frac{8}{3} mā te pūrua i te taurunga me te tauraro o te hautanga.

$$x^{2}+\frac{16}{3}x+\frac{64}{9}=\frac{5}{3}+\frac{64}{9}$$

Tāpiri \frac{5}{3} ki te \frac{64}{9} mā te kimi i te tauraro pātahi me te tāpiri i ngā taurunga. Ka whakaiti i te hautanga ki ngā kīanga tau iti rawa e taea ana.

$$x^{2}+\frac{16}{3}x+\frac{64}{9}=\frac{79}{9}$$

Tauwehea x^{2}+\frac{16}{3}x+\frac{64}{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}.

$$\left(x+\frac{8}{3}\right)^{2}=\frac{79}{9}$$

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

$$\sqrt{\left(x+\frac{8}{3}\right)^{2}}=\sqrt{\frac{79}{9}}$$

Whakarūnātia.

$$x+\frac{8}{3}=\frac{\sqrt{79}}{3} x+\frac{8}{3}=-\frac{\sqrt{79}}{3}$$

Me tango \frac{8}{3} mai i ngā taha e rua o te whārite.

$$x=\frac{\sqrt{79}-8}{3} x=\frac{-\sqrt{79}-8}{3}$$