Whakaoti i te 4x^2-28=0

$$4 x ^ { 2 } - 28 = 0$$

Whakaoti mō x

$$x=\sqrt{7}\approx 2.645751311$$

$$x=-\sqrt{7}\approx -2.645751311$$

Ngā Upane mā te Kimi Pūtakerua

Me tāpiri te 28 ki ngā taha e rua. Ko te tau i tāpiria he kore ka hua koia tonu.

$$4x^{2}=28$$

Whakawehea ngā taha e rua ki te 4.

$$x^{2}=\frac{28}{4}$$

Whakawehea te 28 ki te 4, kia riro ko 7.

$$x^{2}=7$$

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

$$x=\sqrt{7} x=-\sqrt{7}$$

Ngā Upane e Whakamahi ana i te Tikanga Tātai Pūrua

Ko ngā tikanga tātai pūrua pēnei i tēnei nā, me te kīanga tau x^{2} engari kāore he kīanga tau x, ka taea tonu te whakaoti mā te whakamahi i te tikanga tātai pūrua, \frac{-b±\sqrt{b^{2}-4ac}}{2a}, ina tuhia ki te tānga ngahuru: ax^{2}+bx+c=0.

$$4x^{2}-28=0$$

Kei te āhua arowhānui tēnei whārite: ax^{2}+bx+c=0. Me whakakapi 4 mō a, 0 mō b, me -28 mō c i te tikanga tātai pūrua, \frac{-b±\sqrt{b^{2}-4ac}}{2a}.

$$x=\frac{0±\sqrt{0^{2}-4\times 4\left(-28\right)}}{2\times 4}$$

Pūrua 0.

$$x=\frac{0±\sqrt{-4\times 4\left(-28\right)}}{2\times 4}$$

Whakareatia -4 ki te 4.

$$x=\frac{0±\sqrt{-16\left(-28\right)}}{2\times 4}$$

Whakareatia -16 ki te -28.

$$x=\frac{0±\sqrt{448}}{2\times 4}$$

Tuhia te pūtakerua o te 448.

$$x=\frac{0±8\sqrt{7}}{2\times 4}$$

Whakareatia 2 ki te 4.

$$x=\frac{0±8\sqrt{7}}{8}$$

Nā, me whakaoti te whārite x=\frac{0±8\sqrt{7}}{8} ina he tāpiri te ±.

$$x=\sqrt{7}$$

Nā, me whakaoti te whārite x=\frac{0±8\sqrt{7}}{8} ina he tango te ±.

$$x=-\sqrt{7}$$

Kua oti te whārite te whakatau.

$$x=\sqrt{7} x=-\sqrt{7}$$