Whakaoti i te 8x^2-6x-4=0

$$8 { x }^{ 2 } -6x-4=0$$

Whakaoti mō x

$$x = \frac{\sqrt{41} + 3}{8} \approx 1.17539053$$

$$x=\frac{3-\sqrt{41}}{8}\approx -0.42539053$$

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.

$$8x^{2}-6x-4=0$$

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

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

Pūrua -6.

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

Whakareatia -4 ki te 8.

$$x=\frac{-\left(-6\right)±\sqrt{36-32\left(-4\right)}}{2\times 8}$$

Whakareatia -32 ki te -4.

$$x=\frac{-\left(-6\right)±\sqrt{36+128}}{2\times 8}$$

Tāpiri 36 ki te 128.

$$x=\frac{-\left(-6\right)±\sqrt{164}}{2\times 8}$$

Tuhia te pūtakerua o te 164.

$$x=\frac{-\left(-6\right)±2\sqrt{41}}{2\times 8}$$

Ko te tauaro o -6 ko 6.

$$x=\frac{6±2\sqrt{41}}{2\times 8}$$

Whakareatia 2 ki te 8.

$$x=\frac{6±2\sqrt{41}}{16}$$

Nā, me whakaoti te whārite x=\frac{6±2\sqrt{41}}{16} ina he tāpiri te ±. Tāpiri 6 ki te 2\sqrt{41}.

$$x=\frac{2\sqrt{41}+6}{16}$$

Whakawehe 6+2\sqrt{41} ki te 16.

$$x=\frac{\sqrt{41}+3}{8}$$

Nā, me whakaoti te whārite x=\frac{6±2\sqrt{41}}{16} ina he tango te ±. Tango 2\sqrt{41} mai i 6.

$$x=\frac{6-2\sqrt{41}}{16}$$

Whakawehe 6-2\sqrt{41} ki te 16.

$$x=\frac{3-\sqrt{41}}{8}$$

Kua oti te whārite te whakatau.

$$x=\frac{\sqrt{41}+3}{8} x=\frac{3-\sqrt{41}}{8}$$

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.

$$8x^{2}-6x-4=0$$

Me tāpiri 4 ki ngā taha e rua o te whārite.

$$8x^{2}-6x-4-\left(-4\right)=-\left(-4\right)$$

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

$$8x^{2}-6x=-\left(-4\right)$$

Tango -4 mai i 0.

$$8x^{2}-6x=4$$

Whakawehea ngā taha e rua ki te 8.

$$\frac{8x^{2}-6x}{8}=\frac{4}{8}$$

Mā te whakawehe ki te 8 ka wetekia te whakareanga ki te 8.

$$x^{2}+\left(-\frac{6}{8}\right)x=\frac{4}{8}$$

Whakahekea te hautanga \frac{-6}{8} ki ōna wāhi pāpaku rawa mā te tango me te whakakore i te 2.

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

Whakahekea te hautanga \frac{4}{8} ki ōna wāhi pāpaku rawa mā te tango me te whakakore i te 4.

$$x^{2}-\frac{3}{4}x=\frac{1}{2}$$

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

$$x^{2}-\frac{3}{4}x+\left(-\frac{3}{8}\right)^{2}=\frac{1}{2}+\left(-\frac{3}{8}\right)^{2}$$

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

$$x^{2}-\frac{3}{4}x+\frac{9}{64}=\frac{1}{2}+\frac{9}{64}$$

Tāpiri \frac{1}{2} ki te \frac{9}{64} 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.

$$x^{2}-\frac{3}{4}x+\frac{9}{64}=\frac{41}{64}$$

Tauwehea x^{2}-\frac{3}{4}x+\frac{9}{64}. 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}.

$$\left(x-\frac{3}{8}\right)^{2}=\frac{41}{64}$$

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

$$\sqrt{\left(x-\frac{3}{8}\right)^{2}}=\sqrt{\frac{41}{64}}$$

Whakarūnātia.

$$x-\frac{3}{8}=\frac{\sqrt{41}}{8} x-\frac{3}{8}=-\frac{\sqrt{41}}{8}$$

Me tāpiri \frac{3}{8} ki ngā taha e rua o te whārite.

$$x=\frac{\sqrt{41}+3}{8} x=\frac{3-\sqrt{41}}{8}$$