Whakaoti i te {l}{5x-7y=-9}{-2x-y=-4}

$$\left. \begin{array} { l } { 5 x - 7 y = - 9 } \\ { - 2 x - y = - 4 } \end{array} \right.$$

Whakaoti mō x, y

$$x=1$$

$$y=2$$

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.

$$5x-7y=-9,-2x-y=-4$$

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

$$5x-7y=-9$$

Me tāpiri 7y ki ngā taha e rua o te whārite.

$$5x=7y-9$$

Whakawehea ngā taha e rua ki te 5.

$$x=\frac{1}{5}\left(7y-9\right)$$

Whakareatia \frac{1}{5} ki te 7y-9.

$$x=\frac{7}{5}y-\frac{9}{5}$$

Whakakapia te \frac{7y-9}{5} mō te x ki tērā atu whārite, -2x-y=-4.

$$-2\left(\frac{7}{5}y-\frac{9}{5}\right)-y=-4$$

Whakareatia -2 ki te \frac{7y-9}{5}.

$$-\frac{14}{5}y+\frac{18}{5}-y=-4$$

Tāpiri -\frac{14y}{5} ki te -y.

$$-\frac{19}{5}y+\frac{18}{5}=-4$$

Me tango \frac{18}{5} mai i ngā taha e rua o te whārite.

$$-\frac{19}{5}y=-\frac{38}{5}$$

Whakawehea ngā taha e rua o te whārite ki te -\frac{19}{5}, he ōrite ki te whakarea i ngā taha e rua ki te tau huripoki o te hautanga.

$$y=2$$

Whakaurua te 2 mō y ki x=\frac{7}{5}y-\frac{9}{5}. I te mea kotahi anake te taurangi kei te whārite i puta, ka taea e koe te whakaoti mō x hāngai tonu.

$$x=\frac{7}{5}\times 2-\frac{9}{5}$$

Whakareatia \frac{7}{5} ki te 2.

$$x=\frac{14-9}{5}$$

Tāpiri -\frac{9}{5} ki te \frac{14}{5} mā te kimi i te tauraro pātahi me te tāpiri i ngā taurunga. Ka whakaiti i te hautanga ki ngā kīanga tau iti rawa e taea ana.

$$x=1$$

Kua oti te pūnaha te whakatau.

$$x=1,y=2$$

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.

$$5x-7y=-9,-2x-y=-4$$

Tuhia ngā whārite ki te tikanga tātai poukapa.

$$\left(\begin{matrix}5&-7\\-2&-1\end{matrix}\right)\left(\begin{matrix}x\\y\end{matrix}\right)=\left(\begin{matrix}-9\\-4\end{matrix}\right)$$

Whakarea mauī i te whārite ki te poukapa kōaro o \left(\begin{matrix}5&-7\\-2&-1\end{matrix}\right).

$$inverse(\left(\begin{matrix}5&-7\\-2&-1\end{matrix}\right))\left(\begin{matrix}5&-7\\-2&-1\end{matrix}\right)\left(\begin{matrix}x\\y\end{matrix}\right)=inverse(\left(\begin{matrix}5&-7\\-2&-1\end{matrix}\right))\left(\begin{matrix}-9\\-4\end{matrix}\right)$$

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

$$\left(\begin{matrix}1&0\\0&1\end{matrix}\right)\left(\begin{matrix}x\\y\end{matrix}\right)=inverse(\left(\begin{matrix}5&-7\\-2&-1\end{matrix}\right))\left(\begin{matrix}-9\\-4\end{matrix}\right)$$

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

$$\left(\begin{matrix}x\\y\end{matrix}\right)=inverse(\left(\begin{matrix}5&-7\\-2&-1\end{matrix}\right))\left(\begin{matrix}-9\\-4\end{matrix}\right)$$

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.

$$\left(\begin{matrix}x\\y\end{matrix}\right)=\left(\begin{matrix}-\frac{1}{5\left(-1\right)-\left(-7\left(-2\right)\right)}&-\frac{-7}{5\left(-1\right)-\left(-7\left(-2\right)\right)}\\-\frac{-2}{5\left(-1\right)-\left(-7\left(-2\right)\right)}&\frac{5}{5\left(-1\right)-\left(-7\left(-2\right)\right)}\end{matrix}\right)\left(\begin{matrix}-9\\-4\end{matrix}\right)$$

Mahia ngā tātaitanga.

$$\left(\begin{matrix}x\\y\end{matrix}\right)=\left(\begin{matrix}\frac{1}{19}&-\frac{7}{19}\\-\frac{2}{19}&-\frac{5}{19}\end{matrix}\right)\left(\begin{matrix}-9\\-4\end{matrix}\right)$$

Whakareatia ngā poukapa.

$$\left(\begin{matrix}x\\y\end{matrix}\right)=\left(\begin{matrix}\frac{1}{19}\left(-9\right)-\frac{7}{19}\left(-4\right)\\-\frac{2}{19}\left(-9\right)-\frac{5}{19}\left(-4\right)\end{matrix}\right)$$

Mahia ngā tātaitanga.

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

Tangohia ngā huānga poukapa x me y.

$$x=1,y=2$$

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.

$$5x-7y=-9,-2x-y=-4$$

Kia ōrite ai a 5x 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 5.

$$-2\times 5x-2\left(-7\right)y=-2\left(-9\right),5\left(-2\right)x+5\left(-1\right)y=5\left(-4\right)$$

Whakarūnātia.

$$-10x+14y=18,-10x-5y=-20$$

Me tango -10x-5y=-20 mai i -10x+14y=18 mā te tango i ngā kīanga tau ōrite i ia taha o te tohu ōrite.

$$-10x+10x+14y+5y=18+20$$

Tāpiri -10x ki te 10x. Ka whakakore atu ngā kupu -10x me 10x, ka toe he whārite me tētahi taurangi kotahi ka taea te whakaoti.

$$14y+5y=18+20$$

Tāpiri 14y ki te 5y.

$$19y=18+20$$

Tāpiri 18 ki te 20.

$$19y=38$$

Whakawehea ngā taha e rua ki te 19.

$$y=2$$

Whakaurua te 2 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.

$$-2x-2=-4$$

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

$$-2x=-2$$

Whakawehea ngā taha e rua ki te -2.

$$x=1$$

Kua oti te pūnaha te whakatau.

$$x=1,y=2$$