How do you solve the following system?: $y=2x + 3 , 9y = -3x - 9$

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Answer 1 · 2016-05-25T16:26:43

The solution for the system of equations is:
$color(blue)(x = -12/7$

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

$color(blue)(y = 2x +3$ ..............equation $(1)$
$9y = -3x - 9$ ....equation $(2)$

Substituting equation $1$ in equation $2:$

$9y = -3x - 9$

$9 xx (color(blue)( 2x +3)) = -3x - 9$

$18x + 27 = -3x - 9$

$18x + 3x = - 9 -27$

$21x = -36$

$x = -36/21$

$color(blue)(x = -12/7$

Finding $y$ from equation $(1):$
$y = 2x +3$

$y = 2 xx (-12/7) +3$

$y = -24/7 +3$

$y = -24/7 +21/7$

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

How do you solve the following system?: y=2x + 3 , 9y = -3x - 9 y=2x + 3 , 9y = -3x - 9