Answer
$(-3,-1)$, $(-3,1)$, $(3,-1)$, $(3,1)$
Work Step by Step
Re-arrange the given two equations and then use the addition method to get
$8x^2+12y^2=84$ and $9x^2-12y^2=69$
$8x^2+12y^2+9x^2-12y^2=69+84$
This gives: $x^2=9 \implies x=3,-3$
when $x=3$ then we have $(2)(9)+3y^2=21 \implies y^2=1$
This gives: $y=1,-1$
Hence, our answers are: $(-3,-1)$, $(-3,1)$, $(3,-1)$, $(3,1)$
