How do you solve by substitution $x - 2y = -1$ and $2x - y = 4$ ?

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Answer 1 · 2015-06-10T09:58:11

The solution for the system of equations is
$color(blue)(x = 3 , y =2$

$x - 2y = -1$
$x =color(blue)( -1+2y$ ........equation $(1)$

$2x - y = 4$ ............equation $(2)$

Substituting equation $1$ in $2$ to find $y$
$2color(blue)((-1+2y)) - y = 4$
$-2 +4y -y = 4$
$3y =6$
$color(blue)(y=2$

Substituting $y$ in equation $1$ to find $x$ :
$x = -1+2y$
$x = -1+4$
$color(blue)(x = 3$

How do you solve by substitution x - 2y = -1x - 2y = -1 and 2x - y = 42x - y = 4?