How do you solve $x+y=7$ and $2x+3y=20$ ?

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Answer 1 · 2015-05-18T00:13:26

We can isolate one variable in one equation and substitute it in the other one.

Let's isolate $x$ in the first equation and then substitute it in the second one:

$x=7-y$

Then

$2(7-y)+3y=20$
$14-2y+3y=20$
$y=6$

If $y=6$ and $x=7-y$ , then $x=7-6$ , $x=1$ !

There you have: $x=1$ and $y=6$ !

How do you solve x+y=7x+y=7 and 2x+3y=202x+3y=20?