Whakaoti i te {l}{x=y+3}{7x-5y=19}

$$\left\{ \begin{array} { l } { x = y + 3 } \\ { 7 x - 5 y = 19 } \end{array} \right.$$

Whakaoti mō x, y

$$x=2$$

$$y=-1$$

Ngā Upane e Whakamahi ana i te Whakakapinga

Whakaarohia te whārite tuatahi. Tangohia te y mai i ngā taha e rua.

$$x-y=3$$

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.

$$x-y=3,7x-5y=19$$

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

$$x-y=3$$

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

$$x=y+3$$

Whakakapia te y+3 mō te x ki tērā atu whārite, 7x-5y=19.

$$7\left(y+3\right)-5y=19$$

Whakareatia 7 ki te y+3.

$$7y+21-5y=19$$

Tāpiri 7y ki te -5y.

$$2y+21=19$$

Me tango 21 mai i ngā taha e rua o te whārite.

$$2y=-2$$

Whakawehea ngā taha e rua ki te 2.

$$y=-1$$

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

$$x=-1+3$$

Tāpiri 3 ki te -1.

$$x=2$$

Kua oti te pūnaha te whakatau.

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

Ngā Upane e Whakamahi ana i Ngā Poukapa

Whakaarohia te whārite tuatahi. Tangohia te y mai i ngā taha e rua.

$$x-y=3$$

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

$$x-y=3,7x-5y=19$$

Tuhia ngā whārite ki te tikanga tātai poukapa.

$$\left(\begin{matrix}1&-1\\7&-5\end{matrix}\right)\left(\begin{matrix}x\\y\end{matrix}\right)=\left(\begin{matrix}3\\19\end{matrix}\right)$$

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

$$inverse(\left(\begin{matrix}1&-1\\7&-5\end{matrix}\right))\left(\begin{matrix}1&-1\\7&-5\end{matrix}\right)\left(\begin{matrix}x\\y\end{matrix}\right)=inverse(\left(\begin{matrix}1&-1\\7&-5\end{matrix}\right))\left(\begin{matrix}3\\19\end{matrix}\right)$$

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

$$\left(\begin{matrix}1&0\\0&1\end{matrix}\right)\left(\begin{matrix}x\\y\end{matrix}\right)=inverse(\left(\begin{matrix}1&-1\\7&-5\end{matrix}\right))\left(\begin{matrix}3\\19\end{matrix}\right)$$

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

$$\left(\begin{matrix}x\\y\end{matrix}\right)=inverse(\left(\begin{matrix}1&-1\\7&-5\end{matrix}\right))\left(\begin{matrix}3\\19\end{matrix}\right)$$

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.

$$\left(\begin{matrix}x\\y\end{matrix}\right)=\left(\begin{matrix}-\frac{5}{-5-\left(-7\right)}&-\frac{-1}{-5-\left(-7\right)}\\-\frac{7}{-5-\left(-7\right)}&\frac{1}{-5-\left(-7\right)}\end{matrix}\right)\left(\begin{matrix}3\\19\end{matrix}\right)$$

Mahia ngā tātaitanga.

$$\left(\begin{matrix}x\\y\end{matrix}\right)=\left(\begin{matrix}-\frac{5}{2}&\frac{1}{2}\\-\frac{7}{2}&\frac{1}{2}\end{matrix}\right)\left(\begin{matrix}3\\19\end{matrix}\right)$$

Whakareatia ngā poukapa.

$$\left(\begin{matrix}x\\y\end{matrix}\right)=\left(\begin{matrix}-\frac{5}{2}\times 3+\frac{1}{2}\times 19\\-\frac{7}{2}\times 3+\frac{1}{2}\times 19\end{matrix}\right)$$

Mahia ngā tātaitanga.

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

Tangohia ngā huānga poukapa x me y.

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

Ngā Upane e Whakamahi i te Tangohanga

Whakaarohia te whārite tuatahi. Tangohia te y mai i ngā taha e rua.

$$x-y=3$$

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.

$$x-y=3,7x-5y=19$$

Kia ōrite ai a x me 7x, whakareatia ngā kīanga tau katoa kei ia taha o te whārite tuatahi ki te 7 me ngā kīanga tau katoa kei ia taha o te whārite tuarua ki te 1.

$$7x+7\left(-1\right)y=7\times 3,7x-5y=19$$

Whakarūnātia.

$$7x-7y=21,7x-5y=19$$

Me tango 7x-5y=19 mai i 7x-7y=21 mā te tango i ngā kīanga tau ōrite i ia taha o te tohu ōrite.

$$7x-7x-7y+5y=21-19$$

Tāpiri 7x ki te -7x. Ka whakakore atu ngā kupu 7x me -7x, ka toe he whārite me tētahi taurangi kotahi ka taea te whakaoti.

$$-7y+5y=21-19$$

Tāpiri -7y ki te 5y.

$$-2y=21-19$$

Tāpiri 21 ki te -19.

$$-2y=2$$

Whakawehea ngā taha e rua ki te -2.

$$y=-1$$

Whakaurua te -1 mō y ki 7x-5y=19. I te mea kotahi anake te taurangi kei te whārite i puta, ka taea e koe te whakaoti mō x hāngai tonu.

$$7x-5\left(-1\right)=19$$

Whakareatia -5 ki te -1.

$$7x+5=19$$

Me tango 5 mai i ngā taha e rua o te whārite.

$$7x=14$$

Whakawehea ngā taha e rua ki te 7.

$$x=2$$

Kua oti te pūnaha te whakatau.

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