Convergence of concave mirror can be decreased by dipping in

For Concave Mirror

The linear magnification of a concave mirror can be positive or negative. Why?

Concave mirror is called a converging mirror

We use concave mirrors as rear view mirrors.

Assertion : If magnification of real object is -2. Then, it is definitely a concave mirror. Reason : Only concave mirror can make real images of real objects.

Assertion : If magnification of real object is -2. Then, it is definitely a concave mirror. Reason : Only concave mirror can make real images of real objects.

How can you distinguish between a plane mirror, a concave mirror and convex mirror just by looking at them ?