Whakaoti i te 5x^2+7x=2

$$5 x ^ { 2 } + 7 x = 2$$

Whakaoti mō x

$$x=\frac{\sqrt{89}-7}{10}\approx 0.243398113$$

$$x=\frac{-\sqrt{89}-7}{10}\approx -1.643398113$$

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.

$$5x^{2}+7x=2$$

Me tango 2 mai i ngā taha e rua o te whārite.

$$5x^{2}+7x-2=2-2$$

Mā te tango i te 2 i a ia ake anō ka toe ko te 0.

$$5x^{2}+7x-2=0$$

Kei te āhua arowhānui tēnei whārite: ax^{2}+bx+c=0. Me whakakapi 5 mō a, 7 mō b, me -2 mō c i te tikanga tātai pūrua, \frac{-b±\sqrt{b^{2}-4ac}}{2a}.

$$x=\frac{-7±\sqrt{7^{2}-4\times 5\left(-2\right)}}{2\times 5}$$

Pūrua 7.

$$x=\frac{-7±\sqrt{49-4\times 5\left(-2\right)}}{2\times 5}$$

Whakareatia -4 ki te 5.

$$x=\frac{-7±\sqrt{49-20\left(-2\right)}}{2\times 5}$$

Whakareatia -20 ki te -2.

$$x=\frac{-7±\sqrt{49+40}}{2\times 5}$$

Tāpiri 49 ki te 40.

$$x=\frac{-7±\sqrt{89}}{2\times 5}$$

Whakareatia 2 ki te 5.

$$x=\frac{-7±\sqrt{89}}{10}$$

Nā, me whakaoti te whārite x=\frac{-7±\sqrt{89}}{10} ina he tāpiri te ±. Tāpiri -7 ki te \sqrt{89}.

$$x=\frac{\sqrt{89}-7}{10}$$

Nā, me whakaoti te whārite x=\frac{-7±\sqrt{89}}{10} ina he tango te ±. Tango \sqrt{89} mai i -7.

$$x=\frac{-\sqrt{89}-7}{10}$$

Kua oti te whārite te whakatau.

$$x=\frac{\sqrt{89}-7}{10} x=\frac{-\sqrt{89}-7}{10}$$

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.

$$5x^{2}+7x=2$$

Whakawehea ngā taha e rua ki te 5.

$$\frac{5x^{2}+7x}{5}=\frac{2}{5}$$

Mā te whakawehe ki te 5 ka wetekia te whakareanga ki te 5.

$$x^{2}+\frac{7}{5}x=\frac{2}{5}$$

Whakawehea te \frac{7}{5}, te tau whakarea o te kīanga tau x, ki te 2 kia riro ai te \frac{7}{10}. Nā, tāpiria te pūrua o te \frac{7}{10} ki ngā taha e rua o te whārite. Mā konei e pūrua tika tonu ai te taha mauī o te whārite.

$$x^{2}+\frac{7}{5}x+\left(\frac{7}{10}\right)^{2}=\frac{2}{5}+\left(\frac{7}{10}\right)^{2}$$

Pūruatia \frac{7}{10} mā te pūrua i te taurunga me te tauraro o te hautanga.

$$x^{2}+\frac{7}{5}x+\frac{49}{100}=\frac{2}{5}+\frac{49}{100}$$

Tāpiri \frac{2}{5} ki te \frac{49}{100} 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.

$$x^{2}+\frac{7}{5}x+\frac{49}{100}=\frac{89}{100}$$

Tauwehea x^{2}+\frac{7}{5}x+\frac{49}{100}. 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}.

$$\left(x+\frac{7}{10}\right)^{2}=\frac{89}{100}$$

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

$$\sqrt{\left(x+\frac{7}{10}\right)^{2}}=\sqrt{\frac{89}{100}}$$

Whakarūnātia.

$$x+\frac{7}{10}=\frac{\sqrt{89}}{10} x+\frac{7}{10}=-\frac{\sqrt{89}}{10}$$

Me tango \frac{7}{10} mai i ngā taha e rua o te whārite.

$$x=\frac{\sqrt{89}-7}{10} x=\frac{-\sqrt{89}-7}{10}$$