Question

an object is placed at 30cm in front of concave lens of focal length 10cn . At what distance from the lens image is formed ?

Answer 1

u=-30cm
f=10cm
v=?
1/u-1/v=1/f
1/-30-1/v=1/10
1/-30-1/10=1/v
1/30+1/10=v
1/30+3/30=v
4/30=v
v=30/4
v=7.5cm