Question

answer for the question​

Answer 1

Answer:

1/f - 1/u = 1/v

1/10 - 1/(-20)

(2+1)/20

=3/20 or 0.15

Answer 2

Using the formula

1/f=1/v-1/u

. 1/v=1/u+1/f

1/v=(1/-20)+1/10

1/v= -10/20+20/20

1/v= -10/20

1/v= -1/2

aswer