Science

Math

Humanities

... and beyond

Socratic Meta
Featured Answers

Topics

How do you solve the system of equations: 3x+y=3 and x+2y=-4?

1 Answer

Aug 15, 2015

The solutions are
$x = 2, y = - 3$ $color(blue)(x=2,y=-3$

Explanation:

$3 x + y = 3$ $color(blue)(3x)+y=3$ ................equation $1$ $1$

$x + 2 y = - 4$ $x+2y=-4$ , multiplying this equation by $3$ $3$
$3 x + 6 y = - 12$ $color(blue)(3x)+6y=-12$ ........equation $2$ $2$

Now, we can solve the equations by elimination as $3 x$ $color(blue)(3x)$ is common to both equations.

Subtracting equation $2$ $2$ from $1$ $1$
$cancelcolor(blue)(3x)+y=3$
$-cancelcolor(blue)(3x)-6y=+12$

$-5y=15$
$color(blue)(y=-3$

Finding $x$ by substituting $y$ in equation $2$
$x+2y=-4$
$x=-4-2y$
$x=-4-2*-3$
$x=-4+6$
$color(blue)(x=2$

Related questions

See all questions in Linear Systems with Multiplication

Impact of this question

4780 views around the world

You can reuse this answer
Creative Commons License