Answer
${(-4, 0), (0, 4), (4,0)}$
Work Step by Step
$x^2+y^2=16$
$y=-1/4*x^2+4$
$y=-1/4*x^2+4$
$y-4=-1/4*x^2+4-4$
$y-4=-1/4*x^2$
$-4*(y-4)=-4*-1/4*x^2$
$-4y+16=x^2$
$x^2+y^2=16$
$(-4y+16)+y^2=16$
$y^2-4y+16=16$
$y^2-4y+16-16=16-16$
$y^2-4y=0$
$y(y-4)=0$
$y=0$
$y-4=0$
$y-4+4=0+4$
$y=4$
$y=0$
$x^2+y^2=16$
$x^2+0^2=16$
$x^2+0=16$
$x^2=16$
$\sqrt {x^2} =\sqrt {16}$
$x =±4$
$y=4$
$x^2+y^2=16$
$x^2+4^2=16$
$x^2+16=16$
$x^2+16-16=16-16$
$x^2=0$
$\sqrt {x^2} = \sqrt 0$
$x=0$
