Whakaoti i te {l}{3x+2y=7}{2x-y=7}

$$\left\{ \begin{array} { l } { 3 x + 2 y = 7 } \\ { 2 x - y = 7 } \end{array} \right.$$

Whakaoti mō x, y

$$x=3$$

$$y=-1$$

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.

$$3x+2y=7,2x-y=7$$

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

$$3x+2y=7$$

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

$$3x=-2y+7$$

Whakawehea ngā taha e rua ki te 3.

$$x=\frac{1}{3}\left(-2y+7\right)$$

Whakareatia \frac{1}{3} ki te -2y+7.

$$x=-\frac{2}{3}y+\frac{7}{3}$$

Whakakapia te \frac{-2y+7}{3} mō te x ki tērā atu whārite, 2x-y=7.

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

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

$$-\frac{4}{3}y+\frac{14}{3}-y=7$$

Tāpiri -\frac{4y}{3} ki te -y.

$$-\frac{7}{3}y+\frac{14}{3}=7$$

Me tango \frac{14}{3} mai i ngā taha e rua o te whārite.

$$-\frac{7}{3}y=\frac{7}{3}$$

Whakawehea ngā taha e rua o te whārite ki te -\frac{7}{3}, he ōrite ki te whakarea i ngā taha e rua ki te tau huripoki o te hautanga.

$$y=-1$$

Whakaurua te -1 mō y ki x=-\frac{2}{3}y+\frac{7}{3}. I te mea kotahi anake te taurangi kei te whārite i puta, ka taea e koe te whakaoti mō x hāngai tonu.

$$x=-\frac{2}{3}\left(-1\right)+\frac{7}{3}$$

Whakareatia -\frac{2}{3} ki te -1.

$$x=\frac{2+7}{3}$$

Tāpiri \frac{7}{3} ki te \frac{2}{3} 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.

$$x=3$$

Kua oti te pūnaha te whakatau.

$$x=3,y=-1$$

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.

$$3x+2y=7,2x-y=7$$

Tuhia ngā whārite ki te tikanga tātai poukapa.

$$\left(\begin{matrix}3&2\\2&-1\end{matrix}\right)\left(\begin{matrix}x\\y\end{matrix}\right)=\left(\begin{matrix}7\\7\end{matrix}\right)$$

Whakarea mauī i te whārite ki te poukapa kōaro o \left(\begin{matrix}3&2\\2&-1\end{matrix}\right).

$$inverse(\left(\begin{matrix}3&2\\2&-1\end{matrix}\right))\left(\begin{matrix}3&2\\2&-1\end{matrix}\right)\left(\begin{matrix}x\\y\end{matrix}\right)=inverse(\left(\begin{matrix}3&2\\2&-1\end{matrix}\right))\left(\begin{matrix}7\\7\end{matrix}\right)$$

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

$$\left(\begin{matrix}1&0\\0&1\end{matrix}\right)\left(\begin{matrix}x\\y\end{matrix}\right)=inverse(\left(\begin{matrix}3&2\\2&-1\end{matrix}\right))\left(\begin{matrix}7\\7\end{matrix}\right)$$

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

$$\left(\begin{matrix}x\\y\end{matrix}\right)=inverse(\left(\begin{matrix}3&2\\2&-1\end{matrix}\right))\left(\begin{matrix}7\\7\end{matrix}\right)$$

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.

$$\left(\begin{matrix}x\\y\end{matrix}\right)=\left(\begin{matrix}-\frac{1}{3\left(-1\right)-2\times 2}&-\frac{2}{3\left(-1\right)-2\times 2}\\-\frac{2}{3\left(-1\right)-2\times 2}&\frac{3}{3\left(-1\right)-2\times 2}\end{matrix}\right)\left(\begin{matrix}7\\7\end{matrix}\right)$$

Mahia ngā tātaitanga.

$$\left(\begin{matrix}x\\y\end{matrix}\right)=\left(\begin{matrix}\frac{1}{7}&\frac{2}{7}\\\frac{2}{7}&-\frac{3}{7}\end{matrix}\right)\left(\begin{matrix}7\\7\end{matrix}\right)$$

Whakareatia ngā poukapa.

$$\left(\begin{matrix}x\\y\end{matrix}\right)=\left(\begin{matrix}\frac{1}{7}\times 7+\frac{2}{7}\times 7\\\frac{2}{7}\times 7-\frac{3}{7}\times 7\end{matrix}\right)$$

Mahia ngā tātaitanga.

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

Tangohia ngā huānga poukapa x me y.

$$x=3,y=-1$$

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.

$$3x+2y=7,2x-y=7$$

Kia ōrite ai a 3x 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 3.

$$2\times 3x+2\times 2y=2\times 7,3\times 2x+3\left(-1\right)y=3\times 7$$

Whakarūnātia.

$$6x+4y=14,6x-3y=21$$

Me tango 6x-3y=21 mai i 6x+4y=14 mā te tango i ngā kīanga tau ōrite i ia taha o te tohu ōrite.

$$6x-6x+4y+3y=14-21$$

Tāpiri 6x ki te -6x. Ka whakakore atu ngā kupu 6x me -6x, ka toe he whārite me tētahi taurangi kotahi ka taea te whakaoti.

$$4y+3y=14-21$$

Tāpiri 4y ki te 3y.

$$7y=14-21$$

Tāpiri 14 ki te -21.

$$7y=-7$$

Whakawehea ngā taha e rua ki te 7.

$$y=-1$$

Whakaurua te -1 mō y ki 2x-y=7. I te mea kotahi anake te taurangi kei te whārite i puta, ka taea e koe te whakaoti mō x hāngai tonu.

$$2x-\left(-1\right)=7$$

Me tango 1 mai i ngā taha e rua o te whārite.

$$2x=6$$

Whakawehea ngā taha e rua ki te 2.

$$x=3$$

Kua oti te pūnaha te whakatau.

$$x=3,y=-1$$