How do you find the point of intersection for $x+2y=3$ and $3x-y= -5$ ?

Question

3828 views around the world

You can reuse this answer
Creative Commons License

Answer 1 · 2015-07-08T20:10:00

You use one equation to express one of the variables in terms of the other. Then you substitute that in the other equation.

$3x-y=-5->-y=-3x-5->y=3x+5$

Then:
$x+2*(3x+5)=3->7x+10=3->x=-1$

From the first equation:
$y=3x+5=3*(-1)+5=2$

So the intersection point is $(-1,2)$

Check your answer with the original equations!
$-1+2*2=3and3*(-1)-2=-5$

How do you find the point of intersection for x+2y=3x+2y=3 and 3x-y= -53x-y= -5?