How do you find the solution of the system of equations 3x-y=4 and 6x+2y= -8?

May 8, 2015

$\text{[1] } 3 x - y = 4$
$\text{[2] } 6 x + 2 y = - 8$

$\text{[3] = [1]"xx"2 }$
$6 x - 2 y = 8$

$\text{[4] = [2]-[3] }$
$4 y = - 16$

$\text{[5] }$
$y = - 4$

$\text{[6] substituting [5] into [1] }$
$3 x + 4 = 4$

$\text{[7]}$
$x = \frac{8}{3}$

Solution:
$\left(x , y\right) = \left(\frac{8}{3} , - 4\right)$