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2x^{2}-3x-2=0
Whakareatia ngā taha e rua o te whārite ki te 2.
a+b=-3 ab=2\left(-2\right)=-4
Hei whakaoti i te whārite, whakatauwehea te taha mauī mā te whakarōpū. Tuatahi, me tuhi anō te taha mauī hei 2x^{2}+ax+bx-2. Hei kimi a me b, whakaritea tētahi pūnaha kia whakaoti.
1,-4 2,-2
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 -4.
1-4=-3 2-2=0
Tātaihia te tapeke mō ia takirua.
a=-4 b=1
Ko te otinga te takirua ka hoatu i te tapeke -3.
\left(2x^{2}-4x\right)+\left(x-2\right)
Tuhia anō te 2x^{2}-3x-2 hei \left(2x^{2}-4x\right)+\left(x-2\right).
2x\left(x-2\right)+x-2
Whakatauwehea atu 2x i te 2x^{2}-4x.
\left(x-2\right)\left(2x+1\right)
Whakatauwehea atu te kīanga pātahi x-2 mā te whakamahi i te āhuatanga tātai tohatoha.
x=2 x=-\frac{1}{2}
Hei kimi otinga whārite, me whakaoti te x-2=0 me te 2x+1=0.
2x^{2}-3x-2=0
Whakareatia ngā taha e rua o te whārite ki te 2.
x=\frac{-\left(-3\right)±\sqrt{\left(-3\right)^{2}-4\times 2\left(-2\right)}}{2\times 2}
Kei te āhua arowhānui tēnei whārite: ax^{2}+bx+c=0. Me whakakapi 2 mō a, -3 mō b, me -2 mō c i te tikanga tātai pūrua, \frac{-b±\sqrt{b^{2}-4ac}}{2a}.
x=\frac{-\left(-3\right)±\sqrt{9-4\times 2\left(-2\right)}}{2\times 2}
Pūrua -3.
x=\frac{-\left(-3\right)±\sqrt{9-8\left(-2\right)}}{2\times 2}
Whakareatia -4 ki te 2.
x=\frac{-\left(-3\right)±\sqrt{9+16}}{2\times 2}
Whakareatia -8 ki te -2.
x=\frac{-\left(-3\right)±\sqrt{25}}{2\times 2}
Tāpiri 9 ki te 16.
x=\frac{-\left(-3\right)±5}{2\times 2}
Tuhia te pūtakerua o te 25.
x=\frac{3±5}{2\times 2}
Ko te tauaro o -3 ko 3.
x=\frac{3±5}{4}
Whakareatia 2 ki te 2.
x=\frac{8}{4}
Nā, me whakaoti te whārite x=\frac{3±5}{4} ina he tāpiri te ±. Tāpiri 3 ki te 5.
x=2
Whakawehe 8 ki te 4.
x=-\frac{2}{4}
Nā, me whakaoti te whārite x=\frac{3±5}{4} ina he tango te ±. Tango 5 mai i 3.
x=-\frac{1}{2}
Whakahekea te hautanga \frac{-2}{4} ki ōna wāhi pāpaku rawa mā te tango me te whakakore i te 2.
x=2 x=-\frac{1}{2}
Kua oti te whārite te whakatau.
2x^{2}-3x-2=0
Whakareatia ngā taha e rua o te whārite ki te 2.
2x^{2}-3x=2
Me tāpiri te 2 ki ngā taha e rua. Ko te tau i tāpiria he kore ka hua koia tonu.
\frac{2x^{2}-3x}{2}=\frac{2}{2}
Whakawehea ngā taha e rua ki te 2.
x^{2}-\frac{3}{2}x=\frac{2}{2}
Mā te whakawehe ki te 2 ka wetekia te whakareanga ki te 2.
x^{2}-\frac{3}{2}x=1
Whakawehe 2 ki te 2.
x^{2}-\frac{3}{2}x+\left(-\frac{3}{4}\right)^{2}=1+\left(-\frac{3}{4}\right)^{2}
Whakawehea te -\frac{3}{2}, te tau whakarea o te kīanga tau x, ki te 2 kia riro ai te -\frac{3}{4}. Nā, tāpiria te pūrua o te -\frac{3}{4} 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}{2}x+\frac{9}{16}=1+\frac{9}{16}
Pūruatia -\frac{3}{4} mā te pūrua i te taurunga me te tauraro o te hautanga.
x^{2}-\frac{3}{2}x+\frac{9}{16}=\frac{25}{16}
Tāpiri 1 ki te \frac{9}{16}.
\left(x-\frac{3}{4}\right)^{2}=\frac{25}{16}
Tauwehea x^{2}-\frac{3}{2}x+\frac{9}{16}. 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}.
\sqrt{\left(x-\frac{3}{4}\right)^{2}}=\sqrt{\frac{25}{16}}
Tuhia te pūtakerua o ngā taha e rua o te whārite.
x-\frac{3}{4}=\frac{5}{4} x-\frac{3}{4}=-\frac{5}{4}
Whakarūnātia.
x=2 x=-\frac{1}{2}
Me tāpiri \frac{3}{4} ki ngā taha e rua o te whārite.