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

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Answer 1 · 2018-04-09T11:19:14

$x=2$
$y=3$

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

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:
$x=2$
$y=3$

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