# How do you solve x + y = 5 and 2x + y = 7  using substitution?

Apr 9, 2018

$x = 2$
$y = 3$

#### Explanation:

You can re-arrange equation $x + y = 5$ to get $x = 5 - y$ and then substitute this into the equation $2 x + y = 7$ to get $2 \left(5 - y\right) + y = 7$.

This can then be simplified to $10 - y = 7$ and so $3 - y = 0$ which means $y = 3$.

Substitute $y = 3$ into $x + y = 5$ and you get $x + 3 = 5$, therefore:
$x = 2$
$y = 3$