How do you solve the following system?: $-12x -15y =3, x -16y = -4$

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Answer 1 · 2016-08-01T19:48:26

$x=-1296/2484$
$y=45/207$

$-12x-15y=3" ; "(1)$
$"rearrange the equation (1)"$

$color(green)(-12x)=3+15y" ; "(2)$

$x-16y=-4" ; "(3)$

$"let us expand the equation (3) by -12"$

$color(red)(-12)*(x-16y)=color(red)(-12)(-4)$

$-12x+192y=48$

$color(green)(-12x)=48-192y" ; "(4)$

$"the left side of the equation (2) and (4) are equal"$

$3+15y=48-192y$

$15y+192y=48-3$

$207y=45$

$y=45/207$

$"now use (1) or (3)"$

$-12x-15(45/207)=3$

$-12x-675/207=3$

$-12x=3+675/207$

$-12x=(621+675)/207$

$-12x=1296/207$

$-x=1296/(12*207)$

$x=-1296/2484$

How do you solve the following system?: -12x -15y =3, x -16y = -4-12x -15y =3, x -16y = -4