How do you solve x + y = 1 and 3x – y = 11?

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Answer 1 · 2018-04-11T21:53:08

$y=-2$ and $x=3$ .

You need to use simultaneous equations. Make $x$ or $y$ the subject from one equation and substitute it into the other.

$x=1-y$

Then

$3(1-y)-y=11$

$3-3y-y=11$

$3-4y=11$

$4y=-8$

$y=-2$

If $y=-2$ , substitute back into either equation to find $x$ .

$x-2=1$

$x=3$