How do you solve 5x - 3y = -20 and -3x + 6y = 12?

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Answer 1 · 2015-09-15T16:01:09

The solution is
$color(blue)(x=-4, y=0$

$5x - 3y = -20$ , multiplying this equation by $2$
$10x - color(blue)(6y) = -40$ ......equation $1$

$-3x + color(blue)(6y) = 12$ ......equation $2$

Solving the equation by elimination .

Adding equations $1$ and $2$ results in elimination of $color(blue)(6y$

$10x - cancelcolor(blue)(6y) = -40$
$-3x + cancelcolor(blue)(6y) = 12$

$7x= -28$

$x= -28/7$

$color(blue)(x=-4$

Substituting $x$ in equation $1$ to find $y$
$5x - 3y = -20$

$5x +20 = 3y$

$5*(-4) +20 = 3y$

$-20 +20 = 3y$

$3y=0$

$color(blue)(y=0$