Question

Find focus of mirror for 1/-16+1/-20with formula 1/f=1u+1/v

Answer 1

Answer:

9/-80

Explanation:

1/-16+1/-20

1/f=1/u+1/v

1/f=(1/-16)+(-1/20)

=-1/16-1/20

= (-1(5)-1(4))/80

=(-5-4)/80

=-9/80

=9/-80