How do you solve $x=y+3$ and $x-y^(2)=3y$ using substitution?

Question

3959 views around the world

You can reuse this answer
Creative Commons License

Answer 1 · 2018-06-19T21:38:17

Shown below

$x = y+3" " color(red)((1)$

$x - y^2 = 3y " " color(blue)((2)$

Substitute $color(red)((1)$ into $color(blue)((2)$

$=> (y+3 ) - y^2 = 3y$

$=> y^2 +2y -3 = 0$

$=> ( y-1)(y+3) = 0$

$=> y = 1 , y =-3$

Using $color(red)((1)$

$y=1 => x = 1+3 = 4$

$y =-3 => x = -3 + 3 = 0$

Hence the solutions are $x = 4 , y=1$ and $x = 0 , y=-3$

In coordinate form:

$(4,1)$ and $(0,-3)$

How do you solve x=y+3x=y+3 and x-y^(2)=3yx-y^(2)=3y using substitution?