Question

Solve the following system by the substitution method.

Answer 1

From the 2nd equation we get :
$x=3-2y$
Then we plug in the first equation :
$y^2=(3-2y)^2-9$

so :
$y^2=9-12y+4y^2-9$

we find this equation :

$4y^2-12y=0$

By factorization we get :

$4y(y-3)=0$

thus : $y=0 \text{ or }y=3$

And we can get the values of x