# How do solve the following linear system?:  3x-y=7 , 11x + 3y + 7 = 0 ?

Apr 11, 2016

#### Answer:

The solution for the system of equations is:
color(green)(x = 7 / 10

color(green)(y = (- 49) / 10

#### Explanation:

$3 x - y = 7$ , multiplying by $3$
$9 x - \textcolor{b l u e}{3 y} = 21$.....................equation $\left(1\right)$

$11 x + \textcolor{b l u e}{3 y} = - 7$................equation $\left(2\right)$

Solving by elimination.

Adding equations $1$ and $2$ eliminates color(blue)(3y

$9 x - \cancel{\textcolor{b l u e}{3 y}} = 21$

$11 x + \cancel{\textcolor{b l u e}{3 y}} = - 7$

$20 x = 14$

$x = \frac{14}{20}$

color(green)(x = 7 / 10

Finding $y$ from equation $1$

$3 x - y = 7$

$3 x - 7 = y$

$3 \cdot \textcolor{g r e e n}{\frac{7}{10}} - 7 = y$

$\frac{21}{10} - 7 = y$

$\frac{21 - 70}{10} = y$

$\frac{- 49}{10} = y$

color(green)(y = (- 49) / 10