How do you solve the system using elimination $2x-y=9$ and $x-2y=11$ ?

Question

2386 views around the world

You can reuse this answer
Creative Commons License

Answer 1 · 2015-06-10T18:01:06

The solution for the system of equations is
$color(blue)( x =7/3 and y =-13/3$

$2x-y=9$ , multiplying this equation by $2$
$4x color(blue)(-2y) =18$ .......equation $(1)$
$xcolor(blue)(-2y)=11$ ........equation $(2)$

Subtracting equation $(1)$ from $(2)$ to eliminate $color(blue)(2y$

$xcolor(blue)cancel(-2y)=11$
$-4x color(blue)cancel(+2y) =-18$

$-3x = -7$
$color(blue)(x = 7/3$

Substituting $x$ in the first equation to find $y$

$y = 2x -9$

$y = 2.(7/3) - 9$

$y = 14/3 - 9$
$color(blue)( y = -13/3$

How do you solve the system using elimination 2x-y=9 2x-y=9 and x-2y=11x-2y=11?