How do solve the following linear system?: $x + y= 12 , 3x + 4y = -2$ ?

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Answer 1 · 2018-05-09T05:14:17

$color(green)(x = 50, y = -38$

$x + y = 12, " Eqn (1)"$

$3x + 4y = -2, " Eqn (2)"$

$" Eqn ( 2) - 3 * Eqn (1) gives "$

$3x + 4y -3x -3y = -2 - 36$

$color(green)(y = -38$

Substituting value of y in Eqn (1),

$color(green)(x = 12 + 38 = 50$

How do solve the following linear system?: x + y= 12 , 3x + 4y = -2 x + y= 12 , 3x + 4y = -2 ?