Whakaoti i te {l}{x+2y=1}{-2x+y=-4}

$$\left. \begin{array} { l } { x + 2 y = 1 } \\ { - 2 x + y = - 4 } \end{array} \right.$$

Whakaoti mō x, y

$$x = \frac{9}{5} = 1\frac{4}{5} = 1.8$$

$$y=-\frac{2}{5}=-0.4$$

Ngā Upane e Whakamahi ana i te Whakakapinga

Hei whakaoti i ētahi whārite takirua mā te whakakapinga, me whakaoti tētahi whārite i te tuatahi mō tētahi o ngā taurangi. Ka whakakapi i te otinga mō taua taurangi ki tērā o ngā whārite.

$$x+2y=1,-2x+y=-4$$

Kōwhiria tētahi o ngā whārite ka whakaotia mō te x mā te wehe i te x i te taha mauī o te tohu ōrite.

$$x+2y=1$$

Me tango 2y mai i ngā taha e rua o te whārite.

$$x=-2y+1$$

Whakakapia te -2y+1 mō te x ki tērā atu whārite, -2x+y=-4.

$$-2\left(-2y+1\right)+y=-4$$

Whakareatia -2 ki te -2y+1.

$$4y-2+y=-4$$

Tāpiri 4y ki te y.

$$5y-2=-4$$

Me tāpiri 2 ki ngā taha e rua o te whārite.

$$5y=-2$$

Whakawehea ngā taha e rua ki te 5.

$$y=-\frac{2}{5}$$

Whakaurua te -\frac{2}{5} mō y ki x=-2y+1. I te mea kotahi anake te taurangi kei te whārite i puta, ka taea e koe te whakaoti mō x hāngai tonu.

$$x=-2\left(-\frac{2}{5}\right)+1$$

Whakareatia -2 ki te -\frac{2}{5}.

$$x=\frac{4}{5}+1$$

Tāpiri 1 ki te \frac{4}{5}.

$$x=\frac{9}{5}$$

Kua oti te pūnaha te whakatau.

$$x=\frac{9}{5},y=-\frac{2}{5}$$

Ngā Upane e Whakamahi ana i Ngā Poukapa

Tuhia ngā whārite ki te tānga ngahuru ka whakamahi i ngā poukapa hei whakaoti i te pūnaha o ngā whārite.

$$x+2y=1,-2x+y=-4$$

Tuhia ngā whārite ki te tikanga tātai poukapa.

$$\left(\begin{matrix}1&2\\-2&1\end{matrix}\right)\left(\begin{matrix}x\\y\end{matrix}\right)=\left(\begin{matrix}1\\-4\end{matrix}\right)$$

Whakarea mauī i te whārite ki te poukapa kōaro o \left(\begin{matrix}1&2\\-2&1\end{matrix}\right).

$$inverse(\left(\begin{matrix}1&2\\-2&1\end{matrix}\right))\left(\begin{matrix}1&2\\-2&1\end{matrix}\right)\left(\begin{matrix}x\\y\end{matrix}\right)=inverse(\left(\begin{matrix}1&2\\-2&1\end{matrix}\right))\left(\begin{matrix}1\\-4\end{matrix}\right)$$

Ko te hua o tētahi poukapa me te kōaro ko te poukapa tuakiri.

$$\left(\begin{matrix}1&0\\0&1\end{matrix}\right)\left(\begin{matrix}x\\y\end{matrix}\right)=inverse(\left(\begin{matrix}1&2\\-2&1\end{matrix}\right))\left(\begin{matrix}1\\-4\end{matrix}\right)$$

Whakareatia ngā poukapa kei te taha mauī o te tohu ōrite.

$$\left(\begin{matrix}x\\y\end{matrix}\right)=inverse(\left(\begin{matrix}1&2\\-2&1\end{matrix}\right))\left(\begin{matrix}1\\-4\end{matrix}\right)$$

Mō te poukapa 2\times 2 \left(\begin{matrix}a&b\\c&d\end{matrix}\right), ko te \left(\begin{matrix}\frac{d}{ad-bc}&\frac{-b}{ad-bc}\\\frac{-c}{ad-bc}&\frac{a}{ad-bc}\end{matrix}\right) te poukapa kōaro, nō reira ka taea te tuhi anō te whārite poukapa hei rapanga whakarea poukapa.

$$\left(\begin{matrix}x\\y\end{matrix}\right)=\left(\begin{matrix}\frac{1}{1-2\left(-2\right)}&-\frac{2}{1-2\left(-2\right)}\\-\frac{-2}{1-2\left(-2\right)}&\frac{1}{1-2\left(-2\right)}\end{matrix}\right)\left(\begin{matrix}1\\-4\end{matrix}\right)$$

Mahia ngā tātaitanga.

$$\left(\begin{matrix}x\\y\end{matrix}\right)=\left(\begin{matrix}\frac{1}{5}&-\frac{2}{5}\\\frac{2}{5}&\frac{1}{5}\end{matrix}\right)\left(\begin{matrix}1\\-4\end{matrix}\right)$$

Whakareatia ngā poukapa.

$$\left(\begin{matrix}x\\y\end{matrix}\right)=\left(\begin{matrix}\frac{1}{5}-\frac{2}{5}\left(-4\right)\\\frac{2}{5}+\frac{1}{5}\left(-4\right)\end{matrix}\right)$$

Mahia ngā tātaitanga.

$$\left(\begin{matrix}x\\y\end{matrix}\right)=\left(\begin{matrix}\frac{9}{5}\\-\frac{2}{5}\end{matrix}\right)$$

Tangohia ngā huānga poukapa x me y.

$$x=\frac{9}{5},y=-\frac{2}{5}$$

Ngā Upane e Whakamahi i te Tangohanga

Hei whakaoti mā te tangohanga, ko ngā tau whakarea o tētahi o ngā taurangi me mātua ōrite i ngā whārite e rua kia whakakorehia ai te taurangi ina tangohia tētahi whārite mai i tētahi atu.

$$x+2y=1,-2x+y=-4$$

Kia ōrite ai a x me -2x, whakareatia ngā kīanga tau katoa kei ia taha o te whārite tuatahi ki te -2 me ngā kīanga tau katoa kei ia taha o te whārite tuarua ki te 1.

$$-2x-2\times 2y=-2,-2x+y=-4$$

Whakarūnātia.

$$-2x-4y=-2,-2x+y=-4$$

Me tango -2x+y=-4 mai i -2x-4y=-2 mā te tango i ngā kīanga tau ōrite i ia taha o te tohu ōrite.

$$-2x+2x-4y-y=-2+4$$

Tāpiri -2x ki te 2x. Ka whakakore atu ngā kupu -2x me 2x, ka toe he whārite me tētahi taurangi kotahi ka taea te whakaoti.

$$-4y-y=-2+4$$

Tāpiri -4y ki te -y.

$$-5y=-2+4$$

Tāpiri -2 ki te 4.

$$-5y=2$$

Whakawehea ngā taha e rua ki te -5.

$$y=-\frac{2}{5}$$

Whakaurua te -\frac{2}{5} mō y ki -2x+y=-4. I te mea kotahi anake te taurangi kei te whārite i puta, ka taea e koe te whakaoti mō x hāngai tonu.

$$-2x-\frac{2}{5}=-4$$

Me tāpiri \frac{2}{5} ki ngā taha e rua o te whārite.

$$-2x=-\frac{18}{5}$$

Whakawehea ngā taha e rua ki te -2.

$$x=\frac{9}{5}$$

Kua oti te pūnaha te whakatau.

$$x=\frac{9}{5},y=-\frac{2}{5}$$