How do solve the following linear system?:  x-4y=2 , x-7y=4 ?

Dec 28, 2015

$\left(- \frac{2}{3} , - \frac{2}{3}\right)$

Explanation:

Try to leave $x$ alone in one side of the equation, then equate the other sides;

$x = 2 + 4 y , x = 4 + 7 y$

$2 + 4 y = 4 + 7 y$ $\to$ $- 3 y = 2$
$y = - \frac{2}{3}$

Now, write $- \frac{2}{3}$ instead of $y$ in one of the equations, the value of $x$ will be the same for both of them.

$x = 2 + 4. \left(- \frac{2}{3}\right)$ $\to$ $x = 2 - \frac{8}{3}$
$x = - \frac{2}{3}$