Tolong Nomer 1 dan 2 gampang kok

1. M = f/so-f
= 3= f/20-f
60 - 3f = f
60 = 4f + f
60 = 5f
60/5 = f
12 = f
2. a. jarak bygan
= si = so x f ÷ so - f
= si = 15 x 20 ÷ 15 - 20
= 300 ÷ (-5)
= -60
pembesaran (M) = f/so-f
= 20/15-20
= 20/-5
= -4x
sifat bayangan
karena benda di ruang 1 maka byg d ruang 4 = maya, tegak, diperbesar