Whakaoti i te 9z^2-17z-2

$$9 z ^ { 2 } - 17 z - 2$$

Tauwehe

$$\left(z-2\right)\left(9z+1\right)$$

Ngā Upane Otinga

Whakatauwehea te kīanga mā te whakarōpū. Tuatahi, me tuhi anō te kīanga hei 9z^{2}+az+bz-2. Hei kimi a me b, whakaritea tētahi pūnaha kia whakaoti.

$$a+b=-17 ab=9\left(-2\right)=-18$$

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 -18.

$$1,-18 2,-9 3,-6$$

Tātaihia te tapeke mō ia takirua.

$$1-18=-17 2-9=-7 3-6=-3$$

Ko te otinga te takirua ka hoatu i te tapeke -17.

$$a=-18 b=1$$

Tuhia anō te 9z^{2}-17z-2 hei \left(9z^{2}-18z\right)+\left(z-2\right).

$$\left(9z^{2}-18z\right)+\left(z-2\right)$$

Whakatauwehea atu 9z i te 9z^{2}-18z.

$$9z\left(z-2\right)+z-2$$

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

$$\left(z-2\right)\left(9z+1\right)$$

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.

$$9z^{2}-17z-2=0$$

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.

$$z=\frac{-\left(-17\right)±\sqrt{\left(-17\right)^{2}-4\times 9\left(-2\right)}}{2\times 9}$$

Pūrua -17.

$$z=\frac{-\left(-17\right)±\sqrt{289-4\times 9\left(-2\right)}}{2\times 9}$$

Whakareatia -4 ki te 9.

$$z=\frac{-\left(-17\right)±\sqrt{289-36\left(-2\right)}}{2\times 9}$$

Whakareatia -36 ki te -2.

$$z=\frac{-\left(-17\right)±\sqrt{289+72}}{2\times 9}$$

Tāpiri 289 ki te 72.

$$z=\frac{-\left(-17\right)±\sqrt{361}}{2\times 9}$$

Tuhia te pūtakerua o te 361.

$$z=\frac{-\left(-17\right)±19}{2\times 9}$$

Ko te tauaro o -17 ko 17.

$$z=\frac{17±19}{2\times 9}$$

Whakareatia 2 ki te 9.

$$z=\frac{17±19}{18}$$

Nā, me whakaoti te whārite z=\frac{17±19}{18} ina he tāpiri te ±. Tāpiri 17 ki te 19.

$$z=\frac{36}{18}$$

Whakawehe 36 ki te 18.

$$z=2$$

Nā, me whakaoti te whārite z=\frac{17±19}{18} ina he tango te ±. Tango 19 mai i 17.

$$z=-\frac{2}{18}$$

Whakahekea te hautanga \frac{-2}{18} ki ōna wāhi pāpaku rawa mā te tango me te whakakore i te 2.

$$z=-\frac{1}{9}$$

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 2 mō te x_{1} me te -\frac{1}{9} mō te x_{2}.

$$9z^{2}-17z-2=9\left(z-2\right)\left(z-\left(-\frac{1}{9}\right)\right)$$

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

$$9z^{2}-17z-2=9\left(z-2\right)\left(z+\frac{1}{9}\right)$$

Tāpiri \frac{1}{9} ki te z 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.

$$9z^{2}-17z-2=9\left(z-2\right)\times \frac{9z+1}{9}$$

Whakakorea atu te tauwehe pūnoa nui rawa 9 i roto i te 9 me te 9.

$$9z^{2}-17z-2=\left(z-2\right)\left(9z+1\right)$$

Aromātai

$$\left(z-2\right)\left(9z+1\right)$$