Whakaoti i te 2a^2+a-1

$$2 a ^ { 2 } + a - 1$$

Tauwehe

$$\left(2a-1\right)\left(a+1\right)$$

Ngā Upane Otinga

Whakatauwehea te kīanga mā te whakarōpū. Tuatahi, me tuhi anō te kīanga hei 2a^{2}+pa+qa-1. Hei kimi p me q, whakaritea tētahi pūnaha kia whakaoti.

$$p+q=1 pq=2\left(-1\right)=-2$$

I te mea kua tōraro te pq, he tauaro ngā tohu o p me q. I te mea kua tōrunga te p+q, he nui ake te uara pū o te tau tōrunga i tō te tōraro. Ko te takirua anake pērā ko te otinga pūnaha.

$$p=-1 q=2$$

Tuhia anō te 2a^{2}+a-1 hei \left(2a^{2}-a\right)+\left(2a-1\right).

$$\left(2a^{2}-a\right)+\left(2a-1\right)$$

Whakatauwehea atu a i te 2a^{2}-a.

$$a\left(2a-1\right)+2a-1$$

Whakatauwehea atu te kīanga pātahi 2a-1 mā te whakamahi i te āhuatanga tātai tohatoha.

$$\left(2a-1\right)\left(a+1\right)$$

Ngā Upane e Whakamahi ana i te Tikanga Tātai Pūrua

Ka taea te huamaha pūrua te tauwehe mā te whakamahi i te huringa ax^{2}+bx+c=a\left(x-x_{1}\right)\left(x-x_{2}\right), ina ko x_{1} me x_{2} ngā otinga o te whārite pūrua ax^{2}+bx+c=0.

$$2a^{2}+a-1=0$$

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.

$$a=\frac{-1±\sqrt{1^{2}-4\times 2\left(-1\right)}}{2\times 2}$$

Pūrua 1.

$$a=\frac{-1±\sqrt{1-4\times 2\left(-1\right)}}{2\times 2}$$

Whakareatia -4 ki te 2.

$$a=\frac{-1±\sqrt{1-8\left(-1\right)}}{2\times 2}$$

Whakareatia -8 ki te -1.

$$a=\frac{-1±\sqrt{1+8}}{2\times 2}$$

Tāpiri 1 ki te 8.

$$a=\frac{-1±\sqrt{9}}{2\times 2}$$

Tuhia te pūtakerua o te 9.

$$a=\frac{-1±3}{2\times 2}$$

Whakareatia 2 ki te 2.

$$a=\frac{-1±3}{4}$$

Nā, me whakaoti te whārite a=\frac{-1±3}{4} ina he tāpiri te ±. Tāpiri -1 ki te 3.

$$a=\frac{2}{4}$$

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

$$a=\frac{1}{2}$$

Nā, me whakaoti te whārite a=\frac{-1±3}{4} ina he tango te ±. Tango 3 mai i -1.

$$a=-\frac{4}{4}$$

Whakawehe -4 ki te 4.

$$a=-1$$

Tauwehea te kīanga taketake mā te whakamahi i te ax^{2}+bx+c=a\left(x-x_{1}\right)\left(x-x_{2}\right). Me whakakapi te \frac{1}{2} mō te x_{1} me te -1 mō te x_{2}.

$$2a^{2}+a-1=2\left(a-\frac{1}{2}\right)\left(a-\left(-1\right)\right)$$

Whakamāmātia ngā kīanga katoa o te āhua p-\left(-q\right) ki te p+q.

$$2a^{2}+a-1=2\left(a-\frac{1}{2}\right)\left(a+1\right)$$

Tango \frac{1}{2} mai i a mā te kimi i te tauraro pātahi me te tango i ngā taurunga, ka whakaiti i te hautanga ki ngā kīanga tau iti rawa e taea ana.

$$2a^{2}+a-1=2\times \frac{2a-1}{2}\left(a+1\right)$$

Whakakorea atu te tauwehe pūnoa nui rawa 2 i roto i te 2 me te 2.

$$2a^{2}+a-1=\left(2a-1\right)\left(a+1\right)$$

Aromātai

$$\left(2a-1\right)\left(a+1\right)$$