How do you solve the following system?: $4x +9y =-4 , -21x +2y = 4$

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Answer 1 · 2018-05-30T13:00:46

$x=-44/197$
$y=-68/197$

$4x+9y=-4$ --- (1)
$-21x+2y=4$ --- (2)

From (1),
$4x+9y=-4$
$4x=-4-9y$
$x=1/4(-4-9y)$ --- (3)

Sub (3) into (2)

$-21(1/4(-4-9y))+2y=4$
$-21/4(-4-9y)+2y=4$
$21+189/4y+2y=4$
$197/4y=-17$
$y=-17times4/197$
$y=-68/197$ --- (4)

Sub (4) into (3)
$x=1/4(-4-(9times-68/197))$
$x=-44/197$

How do you solve the following system?: 4x +9y =-4 , -21x +2y = 4 4x +9y =-4 , -21x +2y = 4