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

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Answer 1 · 2016-05-25T16:26:43

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

$y = - \frac{3}{7}$ $color(blue)(y = -3/7$

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

Substituting equation $1$ $1$ in equation $2 :$ $2:$

$9 y = - 3 x - 9$ $9y = -3x - 9$

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

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

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

$21 x = - 36$ $21x = -36$

$x = - \frac{36}{21}$ $x = -36/21$

$x = - \frac{12}{7}$ $color(blue)(x = -12/7$

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

$y = 2 \times (- \frac{12}{7}) + 3$ $y = 2 xx (-12/7) +3$

$y = - \frac{24}{7} + 3$ $y = -24/7 +3$

$y = - \frac{24}{7} + \frac{21}{7}$ $y = -24/7 +21/7$

$y = - \frac{3}{7}$ $color(blue)(y = -3/7$

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