Mohooon baantuin no 5 .....

a. X+3/15 = x/10
15x = 10x+30
5x = 30
X = 6

B. 21/4x+2 = 12/3x-1
63x-21 = 48x+24
15x = 45
X = 3

C. X+2/12 = 2x+1/20
20x+40 = 24x+12
- 4x = - 28
X = 7