Question

Please can explain me the 3 question​

Answer 1

1. U = -12cm

F = -8

1/v + 1/u = 1/f

1/v + 1/-12 = 1/-8

1/v = 1/12 - 1/8

= 4-6/48

1/v = -1/24

V = 24 cm

2. U = -20cm

V = -12cm

1/v + 1/u = 1/f

1/f = 1/-12 + 1/-20

= 5 + 3 / -60 = -8 / 60 = -1 / 6

Answer 2

I think I have given answer for 3 one.