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How do you solve x = y - 1 and y = 4 - 2x?

1 Answer

May 5, 2018

$y = 2$ $y=2$
$x = 1$ $x=1$

Explanation:

$x = y - 1$ $x=y-1$ --- (1)
$y = 4 - 2 x$ $y=4-2x$ --- (2)

Sub (1) into (2)

$y = 4 - 2 (y - 1)$ $y=4-2(y-1)$
$y = 4 - 2 y + 2$ $y=4-2y+2$
$3 y = 6$ $3y=6$
$y = 2$ $y=2$ --- (3)

Sub (3) into (1)
$x = y - 1$ $x=y-1$
$x = 2 - 1$ $x=2-1$
$x = 1$ $x=1$

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