How do you solve the system $y=x-1$ and $x+y=3$ using substitution?

Question

15153 views around the world

You can reuse this answer
Creative Commons License

Answer 1 · 2017-01-20T18:34:33

$x=2$ and $y=1$

$y=x-1$
$x+y=3$

In the second equation, substitute $y$ with its value from the first equation, $color(red)((x-1))$ .

$x+y=3$

$x+color(red)((x-1))=3$

Open the brackets and simplify.

$x+color(red)(x-1)=3$

$2x-1=3$

Add $1$ to each side.

$2x=4$

Divide both sides by $2$ .

$x=2$

In the first equation, substitute $x$ with $color(blue)2$ .

$y=x-1$

$y=color(blue)2-1$

$y=1$

How do you solve the system y=x-1y=x-1 and x+y=3x+y=3 using substitution?