Whakaoti i te 5x^2-8=18x

$$5 x ^ { 2 } - 8 = 18 x$$

Whakaoti mō x

$$x=-\frac{2}{5}=-0.4$$

$$x=4$$

Ngā Upane Whakamahi Tauwehe Mā te Whakarōpū

Tangohia te 18x mai i ngā taha e rua.

$$5x^{2}-8-18x=0$$

Hurinahatia te pūrau ki te āhua tānga ngahuru. Whakaraupapahia ngā kīanga tau mai i te pū teitei rawa ki te mea iti rawa.

$$5x^{2}-18x-8=0$$

Hei whakaoti i te whārite, whakatauwehea te taha mauī mā te whakarōpū. Tuatahi, me tuhi anō te taha mauī hei 5x^{2}+ax+bx-8. Hei kimi a me b, whakaritea tētahi pūnaha kia whakaoti.

$$a+b=-18 ab=5\left(-8\right)=-40$$

I te mea kua tōraro te ab, he tauaro ngā tohu o a me b. I te mea kua tōraro te a+b, he nui ake te uara pū o te tau tōraro i tō te tōrunga. Whakarārangitia ngā tau tōpū takirua pērā katoa ka hoatu i te hua -40.

$$1,-40 2,-20 4,-10 5,-8$$

Tātaihia te tapeke mō ia takirua.

$$1-40=-39 2-20=-18 4-10=-6 5-8=-3$$

Ko te otinga te takirua ka hoatu i te tapeke -18.

$$a=-20 b=2$$

Tuhia anō te 5x^{2}-18x-8 hei \left(5x^{2}-20x\right)+\left(2x-8\right).

$$\left(5x^{2}-20x\right)+\left(2x-8\right)$$

Tauwehea te 5x i te tuatahi me te 2 i te rōpū tuarua.

$$5x\left(x-4\right)+2\left(x-4\right)$$

Whakatauwehea atu te kīanga pātahi x-4 mā te whakamahi i te āhuatanga tātai tohatoha.

$$\left(x-4\right)\left(5x+2\right)$$

Hei kimi otinga whārite, me whakaoti te x-4=0 me te 5x+2=0.

$$x=4 x=-\frac{2}{5}$$

Ngā Upane e Whakamahi ana i te Tikanga Tātai Pūrua

Tangohia te 18x mai i ngā taha e rua.

$$5x^{2}-8-18x=0$$

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.

$$5x^{2}-18x-8=0$$

Kei te āhua arowhānui tēnei whārite: ax^{2}+bx+c=0. Me whakakapi 5 mō a, -18 mō b, me -8 mō c i te tikanga tātai pūrua, \frac{-b±\sqrt{b^{2}-4ac}}{2a}.

$$x=\frac{-\left(-18\right)±\sqrt{\left(-18\right)^{2}-4\times 5\left(-8\right)}}{2\times 5}$$

Pūrua -18.

$$x=\frac{-\left(-18\right)±\sqrt{324-4\times 5\left(-8\right)}}{2\times 5}$$

Whakareatia -4 ki te 5.

$$x=\frac{-\left(-18\right)±\sqrt{324-20\left(-8\right)}}{2\times 5}$$

Whakareatia -20 ki te -8.

$$x=\frac{-\left(-18\right)±\sqrt{324+160}}{2\times 5}$$

Tāpiri 324 ki te 160.

$$x=\frac{-\left(-18\right)±\sqrt{484}}{2\times 5}$$

Tuhia te pūtakerua o te 484.

$$x=\frac{-\left(-18\right)±22}{2\times 5}$$

Ko te tauaro o -18 ko 18.

$$x=\frac{18±22}{2\times 5}$$

Whakareatia 2 ki te 5.

$$x=\frac{18±22}{10}$$

Nā, me whakaoti te whārite x=\frac{18±22}{10} ina he tāpiri te ±. Tāpiri 18 ki te 22.

$$x=\frac{40}{10}$$

Whakawehe 40 ki te 10.

$$x=4$$

Nā, me whakaoti te whārite x=\frac{18±22}{10} ina he tango te ±. Tango 22 mai i 18.

$$x=-\frac{4}{10}$$

Whakahekea te hautanga \frac{-4}{10} ki ōna wāhi pāpaku rawa mā te tango me te whakakore i te 2.

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

Kua oti te whārite te whakatau.

$$x=4 x=-\frac{2}{5}$$

Ngā Upane mō te Whakaoti i te Pūrua

Tangohia te 18x mai i ngā taha e rua.

$$5x^{2}-8-18x=0$$

Me tāpiri te 8 ki ngā taha e rua. Ko te tau i tāpiria he kore ka hua koia tonu.

$$5x^{2}-18x=8$$

Whakawehea ngā taha e rua ki te 5.

$$\frac{5x^{2}-18x}{5}=\frac{8}{5}$$

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

$$x^{2}-\frac{18}{5}x=\frac{8}{5}$$

Whakawehea te -\frac{18}{5}, te tau whakarea o te kīanga tau x, ki te 2 kia riro ai te -\frac{9}{5}. Nā, tāpiria te pūrua o te -\frac{9}{5} ki ngā taha e rua o te whārite. Mā konei e pūrua tika tonu ai te taha mauī o te whārite.

$$x^{2}-\frac{18}{5}x+\left(-\frac{9}{5}\right)^{2}=\frac{8}{5}+\left(-\frac{9}{5}\right)^{2}$$

Pūruatia -\frac{9}{5} mā te pūrua i te taurunga me te tauraro o te hautanga.

$$x^{2}-\frac{18}{5}x+\frac{81}{25}=\frac{8}{5}+\frac{81}{25}$$

Tāpiri \frac{8}{5} ki te \frac{81}{25} 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.

$$x^{2}-\frac{18}{5}x+\frac{81}{25}=\frac{121}{25}$$

Tauwehea x^{2}-\frac{18}{5}x+\frac{81}{25}. 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}.

$$\left(x-\frac{9}{5}\right)^{2}=\frac{121}{25}$$

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

$$\sqrt{\left(x-\frac{9}{5}\right)^{2}}=\sqrt{\frac{121}{25}}$$

Whakarūnātia.

$$x-\frac{9}{5}=\frac{11}{5} x-\frac{9}{5}=-\frac{11}{5}$$

Me tāpiri \frac{9}{5} ki ngā taha e rua o te whārite.

$$x=4 x=-\frac{2}{5}$$