Please solve the 3rd and 4th subdivision.

Dear Student,
(a.)
He should use a concave mirror as it forms a real image on the same side of the mirror.
(b.)
Object distance, u = - 12 cm
Image distance, v = - 48 cm 
Magnification, m = -v/u 
                               = - 48/12    =>  - 4
The minus sign in magnification shows that the image formed is real and inverted.
(c.)
The distance between object and image is = 48 - 12 => 36 cm 
Hence, the image is formed at a distance of 36 cm from the object.
(d.)

Regards