Whakaoti i te {l}{x+y=9}{3x+y=2}

$$\left. \begin{array} { l } { x + y = 9 } \\ { 3 x + y = 2 } \end{array} \right.$$

Whakaoti mō x, y

$$x = -\frac{7}{2} = -3\frac{1}{2} = -3.5$$

$$y = \frac{25}{2} = 12\frac{1}{2} = 12.5$$

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.

$$x+y=9,3x+y=2$$

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

$$x+y=9$$

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

$$x=-y+9$$

Whakakapia te -y+9 mō te x ki tērā atu whārite, 3x+y=2.

$$3\left(-y+9\right)+y=2$$

Whakareatia 3 ki te -y+9.

$$-3y+27+y=2$$

Tāpiri -3y ki te y.

$$-2y+27=2$$

Me tango 27 mai i ngā taha e rua o te whārite.

$$-2y=-25$$

Whakawehea ngā taha e rua ki te -2.

$$y=\frac{25}{2}$$

Whakaurua te \frac{25}{2} mō y ki x=-y+9. I te mea kotahi anake te taurangi kei te whārite i puta, ka taea e koe te whakaoti mō x hāngai tonu.

$$x=-\frac{25}{2}+9$$

Tāpiri 9 ki te -\frac{25}{2}.

$$x=-\frac{7}{2}$$

Kua oti te pūnaha te whakatau.

$$x=-\frac{7}{2},y=\frac{25}{2}$$

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.

$$x+y=9,3x+y=2$$

Tuhia ngā whārite ki te tikanga tātai poukapa.

$$\left(\begin{matrix}1&1\\3&1\end{matrix}\right)\left(\begin{matrix}x\\y\end{matrix}\right)=\left(\begin{matrix}9\\2\end{matrix}\right)$$

Whakarea mauī i te whārite ki te poukapa kōaro o \left(\begin{matrix}1&1\\3&1\end{matrix}\right).

$$inverse(\left(\begin{matrix}1&1\\3&1\end{matrix}\right))\left(\begin{matrix}1&1\\3&1\end{matrix}\right)\left(\begin{matrix}x\\y\end{matrix}\right)=inverse(\left(\begin{matrix}1&1\\3&1\end{matrix}\right))\left(\begin{matrix}9\\2\end{matrix}\right)$$

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

$$\left(\begin{matrix}1&0\\0&1\end{matrix}\right)\left(\begin{matrix}x\\y\end{matrix}\right)=inverse(\left(\begin{matrix}1&1\\3&1\end{matrix}\right))\left(\begin{matrix}9\\2\end{matrix}\right)$$

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

$$\left(\begin{matrix}x\\y\end{matrix}\right)=inverse(\left(\begin{matrix}1&1\\3&1\end{matrix}\right))\left(\begin{matrix}9\\2\end{matrix}\right)$$

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.

$$\left(\begin{matrix}x\\y\end{matrix}\right)=\left(\begin{matrix}\frac{1}{1-3}&-\frac{1}{1-3}\\-\frac{3}{1-3}&\frac{1}{1-3}\end{matrix}\right)\left(\begin{matrix}9\\2\end{matrix}\right)$$

Mahia ngā tātaitanga.

$$\left(\begin{matrix}x\\y\end{matrix}\right)=\left(\begin{matrix}-\frac{1}{2}&\frac{1}{2}\\\frac{3}{2}&-\frac{1}{2}\end{matrix}\right)\left(\begin{matrix}9\\2\end{matrix}\right)$$

Whakareatia ngā poukapa.

$$\left(\begin{matrix}x\\y\end{matrix}\right)=\left(\begin{matrix}-\frac{1}{2}\times 9+\frac{1}{2}\times 2\\\frac{3}{2}\times 9-\frac{1}{2}\times 2\end{matrix}\right)$$

Mahia ngā tātaitanga.

$$\left(\begin{matrix}x\\y\end{matrix}\right)=\left(\begin{matrix}-\frac{7}{2}\\\frac{25}{2}\end{matrix}\right)$$

Tangohia ngā huānga poukapa x me y.

$$x=-\frac{7}{2},y=\frac{25}{2}$$

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.

$$x+y=9,3x+y=2$$

Me tango 3x+y=2 mai i x+y=9 mā te tango i ngā kīanga tau ōrite i ia taha o te tohu ōrite.

$$x-3x+y-y=9-2$$

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

$$x-3x=9-2$$

Tāpiri x ki te -3x.

$$-2x=9-2$$

Tāpiri 9 ki te -2.

$$-2x=7$$

Whakawehea ngā taha e rua ki te -2.

$$x=-\frac{7}{2}$$

Whakaurua te -\frac{7}{2} mō x ki 3x+y=2. I te mea kotahi anake te taurangi kei te whārite i puta, ka taea e koe te whakaoti mō y hāngai tonu.

$$3\left(-\frac{7}{2}\right)+y=2$$

Whakareatia 3 ki te -\frac{7}{2}.

$$-\frac{21}{2}+y=2$$

Me tāpiri \frac{21}{2} ki ngā taha e rua o te whārite.

$$y=\frac{25}{2}$$

Kua oti te pūnaha te whakatau.

$$x=-\frac{7}{2},y=\frac{25}{2}$$