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

Jun 8, 2015

{x=y-1
{y=4-2x
Substitute for $x$ into the second equation:
$y = 4 - 2 \left(y - 1\right)$
$y = 4 - 2 y + 2$
$3 y = 6$
$y = 2$
Back into the first equation:
$x = 2 - 1 = 1$
Solution
$x = 1$
$y = 2$