How do solve the following linear system?: $4x-3y=1 , 3x + y = -20$ ?

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Answer 1 · 2016-01-27T05:53:16

$x=-59/13$
$y=-83/13$

Given -

$4x-3y=1$ -----------------------------(1)
$3x+y=-20$ ---------------------------(2)

Solve the 2nd equation for $y$

$y=-20-3x$

Substitute $y=-20-3x$ in equation (1)

$4x-3(-20-3x)=1$
$4x+60+9x=1$
$13x=1-60$
$x=-59/13$

Substitute $x=-59/13$ in equation (2)

$3(-59/13)+y=-20$
$-177/13+y=-20$
$y=-20+177/13=(-260+177)/13=-83/13$

$y=-83/13$

How do solve the following linear system?: 4x-3y=1 , 3x + y = -20 4x-3y=1 , 3x + y = -20 ?