tolong dong pakai caranya yaa kak

Bab Aljabar Dasar
Matematika SMP Kelas VII

a] x/4 = 5/12
x = 4 . 5 / 12
x = 5/3
x = 1 2/3

b] x/3 = 12/8
x = 3 . 12 / 8
x = 9/2
x = 4 1/2

c] 15/(y + 4) = 20/16
y + 4 = 16 . 15 / 20
y = 12 - 4
y = 8

d] (y - 3)/6 = 21/14
y - 3 = 6 . 21/14
y = 9 + 3
y = 12