Given, equation of the circle $x^2+y^2+2 g x+c=0$, where $c$ is constant and $g$ represents the parameter of a coaxial system and $c\gt0$. We know that the standard equation of a circle is $x^2+y^2+2 g x+2 f y+c=0$. Comparing the given equation with the standard equation, we get centre $\equiv(-g, 0)$ and radius $\sqrt{g^2-c}$. Therefore radius becomes zero, when $g^2-c=0$ or $g= \pm \sqrt{c}$. Therefore $(\sqrt{c}, 0)$ and $(-\sqrt{c}, 0)$ are the limiting points of the coaxial system of circles. Since $c\gt0$, therefore $\sqrt{c}$ is real and limiting points are real and distinct. Thus the co-axial system is said to be touching type.