Answer:
1.
30 x x/30 = 30 x 3/5
x =30 x 3/5
x = 18
2.
5/2 = 30/x
x ⋅ 5/2 = x ⋅ 30/x
5x/2 = 30
2 ⋅ 5x/2 = 2 ⋅ 30
5x = 60
5x/5 = 60/5
x = 12
