Latihan Matematika Wajib Kelas X Sistem Persamaan Dua Variabel
# 5
Pilgan

Diketahui

Himpunan penyelesaian (x,y)\left(x,y\right) untuk sistem persamaan kuadrat-kuadrat dua variabel di atas adalah ....

A

HP={(117,1),(117,1),(117,1),(117,1)}HP=\left\{\left(\sqrt{\frac{1}{17}},1\right),\left(-\sqrt{\frac{1}{17}},1\right),\left(\sqrt{\frac{1}{17}},-1\right),\left(-\sqrt{\frac{1}{17}},-1\right)\right\}

B

HP={(117,3),(117,3),(117,3),(117,3)}HP=\left\{\left(\sqrt{\frac{1}{17}},3\right),\left(-\sqrt{\frac{1}{17}},3\right),\left(\sqrt{\frac{1}{17}},-3\right),\left(-\sqrt{\frac{1}{17}},-3\right)\right\}

C

HP={(15,1),(15,1),(15,1),(15,1)}HP=\left\{\left(\sqrt{\frac{1}{5}},1\right),\left(-\sqrt{\frac{1}{5}},1\right),\left(\sqrt{\frac{1}{5}},-1\right),\left(-\sqrt{\frac{1}{5}},-1\right)\right\}

D

HP={(2,1),(2,1),(2,1),(2,1)}HP=\left\{\left(\sqrt{2},1\right),\left(-\sqrt{2},1\right),\left(\sqrt{2},-1\right),\left(-\sqrt{2},-1\right)\right\}

E

HP={(3,2),(3,2),(3,2),(3,2)}HP=\left\{\left(\sqrt{3},2\right),\left(-\sqrt{3},2\right),\left(\sqrt{3},-2\right),\left(-\sqrt{3},-2\right)\right\}

Pembahasan:

Langkah-langkah dalam menyelesaikan persoalan sistem persamaan kuadrat-kuadrat dua variabel dalam bentuk pecahan adalah

Memisalkan bentuk pecahan sehingga memperoleh sistem persamaan linear dua variabel

Misalkan 1x2=a\frac{1}{x^2}=a dan 1y2=b\frac{1}{y^2}=b sehingga diperoleh sistem persamaan

Melakukan eliminasi pada dua persamaan

Substitusi nilai bb ke salah satu persamaan

a3b=14a-3b=14

a3(1)=14a-3\left(1\right)=14

a3=14a-3=14

a=17a=17

Mencari nilai xx dan yy dari permisalan awal

1x2=a\frac{1}{x^2}=a

1x2=17\frac{1}{x^2}=17

x2=117x^2=\frac{1}{17}

x=±117x=\pm\sqrt{\frac{1}{17}}

1y2=b\frac{1}{y^2}=b

1y2=1\frac{1}{y^2}=1

y2=1y^2=1

y=±1y=\pm1

Sehingga diperoleh solusi (117,1),(117,1),(117,1),(117,1)\left(\sqrt{\frac{1}{17}},1\right),\left(-\sqrt{\frac{1}{17}},1\right),\left(\sqrt{\frac{1}{17}},-1\right),\left(-\sqrt{\frac{1}{17}},-1\right) atau HP={(117,1),(117,1),(117,1),(117,1)}HP=\left\{\left(\sqrt{\frac{1}{17}},1\right),\left(-\sqrt{\frac{1}{17}},1\right),\left(\sqrt{\frac{1}{17}},-1\right),\left(-\sqrt{\frac{1}{17}},-1\right)\right\}