# An object is placed in front of a concave mirror of focal length 20 cm. The image formed is three times the size of the object. Calculate two possible distances of the object from the mirror?

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The Brainliest Answer!

when m=+3

m=-v/u

3=-v/u

v=-3u

1/f=1/v+1/u

-1/20=-1/3u+1/u

1/u=1/3u-1/20

1/u=(20-3u)/60u

60=20-3u [u cancels in the denominator]

-3u=60-20

-3u=40

u = - 40 / 3

when m=-3

repeat the same steps when m = +3

then