Whakaoti i te 5x^2-25x-12=0

$$5 { x }^{ 2 } -25x-12=0$$

Whakaoti mō x

$$x=\frac{\sqrt{865}}{10}+\frac{5}{2}\approx 5.441088234$$

$$x=-\frac{\sqrt{865}}{10}+\frac{5}{2}\approx -0.441088234$$

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.

$$5x^{2}-25x-12=0$$

Kei te āhua arowhānui tēnei whārite: ax^{2}+bx+c=0. Me whakakapi 5 mō a, -25 mō b, me -12 mō c i te tikanga tātai pūrua, \frac{-b±\sqrt{b^{2}-4ac}}{2a}.

$$x=\frac{-\left(-25\right)±\sqrt{\left(-25\right)^{2}-4\times 5\left(-12\right)}}{2\times 5}$$

Pūrua -25.

$$x=\frac{-\left(-25\right)±\sqrt{625-4\times 5\left(-12\right)}}{2\times 5}$$

Whakareatia -4 ki te 5.

$$x=\frac{-\left(-25\right)±\sqrt{625-20\left(-12\right)}}{2\times 5}$$

Whakareatia -20 ki te -12.

$$x=\frac{-\left(-25\right)±\sqrt{625+240}}{2\times 5}$$

Tāpiri 625 ki te 240.

$$x=\frac{-\left(-25\right)±\sqrt{865}}{2\times 5}$$

Ko te tauaro o -25 ko 25.

$$x=\frac{25±\sqrt{865}}{2\times 5}$$

Whakareatia 2 ki te 5.

$$x=\frac{25±\sqrt{865}}{10}$$

Nā, me whakaoti te whārite x=\frac{25±\sqrt{865}}{10} ina he tāpiri te ±. Tāpiri 25 ki te \sqrt{865}.

$$x=\frac{\sqrt{865}+25}{10}$$

Whakawehe 25+\sqrt{865} ki te 10.

$$x=\frac{\sqrt{865}}{10}+\frac{5}{2}$$

Nā, me whakaoti te whārite x=\frac{25±\sqrt{865}}{10} ina he tango te ±. Tango \sqrt{865} mai i 25.

$$x=\frac{25-\sqrt{865}}{10}$$

Whakawehe 25-\sqrt{865} ki te 10.

$$x=-\frac{\sqrt{865}}{10}+\frac{5}{2}$$

Kua oti te whārite te whakatau.

$$x=\frac{\sqrt{865}}{10}+\frac{5}{2} x=-\frac{\sqrt{865}}{10}+\frac{5}{2}$$

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.

$$5x^{2}-25x-12=0$$

Me tāpiri 12 ki ngā taha e rua o te whārite.

$$5x^{2}-25x-12-\left(-12\right)=-\left(-12\right)$$

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

$$5x^{2}-25x=-\left(-12\right)$$

Tango -12 mai i 0.

$$5x^{2}-25x=12$$

Whakawehea ngā taha e rua ki te 5.

$$\frac{5x^{2}-25x}{5}=\frac{12}{5}$$

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

$$x^{2}+\left(-\frac{25}{5}\right)x=\frac{12}{5}$$

Whakawehe -25 ki te 5.

$$x^{2}-5x=\frac{12}{5}$$

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

$$x^{2}-5x+\left(-\frac{5}{2}\right)^{2}=\frac{12}{5}+\left(-\frac{5}{2}\right)^{2}$$

Pūruatia -\frac{5}{2} mā te pūrua i te taurunga me te tauraro o te hautanga.

$$x^{2}-5x+\frac{25}{4}=\frac{12}{5}+\frac{25}{4}$$

Tāpiri \frac{12}{5} ki te \frac{25}{4} 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.

$$x^{2}-5x+\frac{25}{4}=\frac{173}{20}$$

Tauwehea x^{2}-5x+\frac{25}{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}.

$$\left(x-\frac{5}{2}\right)^{2}=\frac{173}{20}$$

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

$$\sqrt{\left(x-\frac{5}{2}\right)^{2}}=\sqrt{\frac{173}{20}}$$

Whakarūnātia.

$$x-\frac{5}{2}=\frac{\sqrt{865}}{10} x-\frac{5}{2}=-\frac{\sqrt{865}}{10}$$

Me tāpiri \frac{5}{2} ki ngā taha e rua o te whārite.

$$x=\frac{\sqrt{865}}{10}+\frac{5}{2} x=-\frac{\sqrt{865}}{10}+\frac{5}{2}$$