Whakaoti i te 3x^2+8x+4=0

$$3 x ^ { 2 } + 8 x + 4 = 0$$

Whakaoti mō x

$$x=-\frac{2}{3}\approx -0.666666667$$

$$x=-2$$

Ngā Upane Whakamahi Tauwehe Mā te Whakarōpū

Hei whakaoti i te whārite, whakatauwehea te taha mauī mā te whakarōpū. Tuatahi, me tuhi anō te taha mauī hei 3x^{2}+ax+bx+4. Hei kimi a me b, whakaritea tētahi pūnaha kia whakaoti.

$$a+b=8 ab=3\times 4=12$$

I te mea kua tōrunga te ab, he ōrite te tohu o a me b. I te mea kua tōrunga te a+b, he tōrunga hoki a a me b. Whakarārangitia ngā tau tōpū takirua pērā katoa ka hoatu i te hua 12.

$$1,12 2,6 3,4$$

Tātaihia te tapeke mō ia takirua.

$$1+12=13 2+6=8 3+4=7$$

Ko te otinga te takirua ka hoatu i te tapeke 8.

$$a=2 b=6$$

Tuhia anō te 3x^{2}+8x+4 hei \left(3x^{2}+2x\right)+\left(6x+4\right).

$$\left(3x^{2}+2x\right)+\left(6x+4\right)$$

Tauwehea te x i te tuatahi me te 2 i te rōpū tuarua.

$$x\left(3x+2\right)+2\left(3x+2\right)$$

Whakatauwehea atu te kīanga pātahi 3x+2 mā te whakamahi i te āhuatanga tātai tohatoha.

$$\left(3x+2\right)\left(x+2\right)$$

Hei kimi otinga whārite, me whakaoti te 3x+2=0 me te x+2=0.

$$x=-\frac{2}{3} x=-2$$

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.

$$3x^{2}+8x+4=0$$

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

$$x=\frac{-8±\sqrt{8^{2}-4\times 3\times 4}}{2\times 3}$$

Pūrua 8.

$$x=\frac{-8±\sqrt{64-4\times 3\times 4}}{2\times 3}$$

Whakareatia -4 ki te 3.

$$x=\frac{-8±\sqrt{64-12\times 4}}{2\times 3}$$

Whakareatia -12 ki te 4.

$$x=\frac{-8±\sqrt{64-48}}{2\times 3}$$

Tāpiri 64 ki te -48.

$$x=\frac{-8±\sqrt{16}}{2\times 3}$$

Tuhia te pūtakerua o te 16.

$$x=\frac{-8±4}{2\times 3}$$

Whakareatia 2 ki te 3.

$$x=\frac{-8±4}{6}$$

Nā, me whakaoti te whārite x=\frac{-8±4}{6} ina he tāpiri te ±. Tāpiri -8 ki te 4.

$$x=-\frac{4}{6}$$

Whakahekea te hautanga \frac{-4}{6} ki ōna wāhi pāpaku rawa mā te tango me te whakakore i te 2.

$$x=-\frac{2}{3}$$

Nā, me whakaoti te whārite x=\frac{-8±4}{6} ina he tango te ±. Tango 4 mai i -8.

$$x=-\frac{12}{6}$$

Whakawehe -12 ki te 6.

$$x=-2$$

Kua oti te whārite te whakatau.

$$x=-\frac{2}{3} x=-2$$

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.

$$3x^{2}+8x+4=0$$

Me tango 4 mai i ngā taha e rua o te whārite.

$$3x^{2}+8x+4-4=-4$$

Mā te tango i te 4 i a ia ake anō ka toe ko te 0.

$$3x^{2}+8x=-4$$

Whakawehea ngā taha e rua ki te 3.

$$\frac{3x^{2}+8x}{3}=-\frac{4}{3}$$

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

$$x^{2}+\frac{8}{3}x=-\frac{4}{3}$$

Whakawehea te \frac{8}{3}, te tau whakarea o te kīanga tau x, ki te 2 kia riro ai te \frac{4}{3}. Nā, tāpiria te pūrua o te \frac{4}{3} ki ngā taha e rua o te whārite. Mā konei e pūrua tika tonu ai te taha mauī o te whārite.

$$x^{2}+\frac{8}{3}x+\left(\frac{4}{3}\right)^{2}=-\frac{4}{3}+\left(\frac{4}{3}\right)^{2}$$

Pūruatia \frac{4}{3} mā te pūrua i te taurunga me te tauraro o te hautanga.

$$x^{2}+\frac{8}{3}x+\frac{16}{9}=-\frac{4}{3}+\frac{16}{9}$$

Tāpiri -\frac{4}{3} ki te \frac{16}{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.

$$x^{2}+\frac{8}{3}x+\frac{16}{9}=\frac{4}{9}$$

Tauwehea x^{2}+\frac{8}{3}x+\frac{16}{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}.

$$\left(x+\frac{4}{3}\right)^{2}=\frac{4}{9}$$

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

$$\sqrt{\left(x+\frac{4}{3}\right)^{2}}=\sqrt{\frac{4}{9}}$$

Whakarūnātia.

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

Me tango \frac{4}{3} mai i ngā taha e rua o te whārite.

$$x=-\frac{2}{3} x=-2$$