Answer
$x^2+y^2=25$
$x^2+y^2=9$
Work Step by Step
We are given the circles:
Circle 1: $r_1=5$
Center: $C_1(0,0)$
Circle 2: $r_2=3$
Center: $C_2(0,0)$
The standard equation of a circle is:
$(x-h)^2+(y-k)^2=r^2$
For both circles we have:
$h=0$
$k=0$
The equation of the first circle is:
$x^2+y^2=r_1^2$
$x^2+y^2=5^2$
$x^2+y^2=25$
The equation of the second circle is:
$x^2+y^2=r_2^2$
$x^2+y^2=3^2$
$x^2+y^2=9$
