Answer:
7.5 cm behind the mirror
Explanation:
Applying,
Using the real is positive convection: All real distance from the mirror are positive
1/f = 1/v+1/u................. Equation 1
Where f = focal length of the mirror, v = image distance, u = object distance
From the question,
f = -12 cm, u = 20 cm
substitute these value into equation 1
1/(-12) = (1/20)+1/v
(-1/12)-(1/20) = 1/v
1/v = (-5-3)/60
1/v = -8/60
v = -60/8
v = -7.5 cm
Hence the image is formed 7.5 cm behind the mirror.
