Whakaoti i te x^2-3x-18<0

$$x ^ { 2 } - 3 x - 18 < 0$$

Whakaoti mō x

$$x\in \left(-3,6\right)$$

Ngā Upane e Whakamahi ana i te Tikanga Tātai Pūrua

Kia whakaotia te koreōrite, me tauwehe te taha mauī. 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.

$$x^{2}-3x-18=0$$

Ka taea ngā whārite katoa o te momo ax^{2}+bx+c=0 te whakaoti mā te ture pūrua: \frac{-b±\sqrt{b^{2}-4ac}}{2a}. Whakakapia te 1 mō te a, te -3 mō te b, me te -18 mō te c i te ture pūrua.

$$x=\frac{-\left(-3\right)±\sqrt{\left(-3\right)^{2}-4\times 1\left(-18\right)}}{2}$$

Mahia ngā tātaitai.

$$x=\frac{3±9}{2}$$

Whakaotia te whārite x=\frac{3±9}{2} ina he tōrunga te ±, ina he tōraro te ±.

$$x=6 x=-3$$

Tuhia anō te koreōrite mā te whakamahi i ngā otinga i whiwhi.

$$\left(x-6\right)\left(x+3\right)<0$$

Kia tōraro te otinga, me tauaro rawa ngā tohu o te x-6 me te x+3. Whakaarohia te tauira ina he tōrunga te x-6 he tōraro te x+3.

$$x-6>0 x+3<0$$

He teka tēnei mō tētahi x ahakoa.

$$x\in \emptyset$$

Whakaarohia te tauira ina he tōrunga te x+3 he tōraro te x-6.

$$x+3>0 x-6<0$$

Te otinga e whakaea i ngā koreōrite e rua ko x\in \left(-3,6\right).

$$x\in \left(-3,6\right)$$

Ko te otinga whakamutunga ko te whakakotahi i ngā otinga kua whiwhi.

$$x\in \left(-3,6\right)$$