What is the solution set for -9x + 3y = -9 and 3x +4y = -9?

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Answer 1 · 2015-08-22T07:38:02

The solutions are
$color(blue)(x=1/5, y=-12/5$

$-color(blue)(9x) + 3y = -9$ .....equation $1$

$3x +4y = -9$ , multiplying by $3$
$color(blue)(9x) +12y = -27$ .....equation $2$

Solving by elimination
Adding equations $1$ and $2$
$-cancelcolor(blue)(9x) + 3y = -9$
$cancelcolor(blue)(9x) +12y = -27$

$15y=-36$
$color(blue)(y=-12/5$

Finding $x$ from equation $2$
$3x +4y = -9$

$3x = -9-4y$

$x = (-9-4y)/3$

$x = 3/15$

$color(blue)(x=1/5$