Bab 4 Persamaan Serentak

Contoh 1:
$x+\frac{1}{4}y=1\text{ dan }{y}^2-8=4x.$

$\begin{array}{l}x+\frac{1}{4}y=1\to (1)\\ y^2-8=4x\to (2)\\ x=1-\frac{1}{4}y\to (3)\end{array}$

$\begin{array}{l}\text{Gantikan }\left(\text{3}\right)\text{ ke dalam }\left(\text{2}\right),\\ y^2-8=4\left(1-\frac{1}{4}y\right)\\ y^2-8=4-\frac{4}{4}y\\ y^2+y-12=0\\ (y+4)(y-3)=0\\ y=-4\mathrm{atau}y=3\end{array}$

$\begin{array}{l}\text{Gantikan nilai-nilai }y\text{ ke dalam }\left(\text{3}\right),\\ \text{apabila }y=-4,\\ x=1-\frac{1}{4}(-4)=2\\ \text{apabila }y=3,\\ x=1-\frac{1}{4}(3)=\frac{1}{4}\end{array}$

Penyelesaian ialah x = 2, y = –4 dan x = ¼, y = 3.