using cross-product method
nalang po please

Step-by-step explanation:
Solution:
30n = 90
30n = 90 n = 90/30
30n = 90 n = 90/30 n = 3
Solution:
21n = 147
21n = 147 n = 147/21
21n = 147 n = 147/21 n = 7
Solution:
3n = 18
3n = 18 n = 18/3
3n = 18 n = 18/3 n = 6
Solution:
8n = 16
8n = 16 n = 16/8
8n = 16 n = 16/8 n = 2
Solution:
4n = 600
n = 600/4
n = 150