Răspuns :
A/B=3/5
-> A/3=B/5=K
-> A=3K
->B=5K
--> 7*3K-3*5K=36
21K-15K=36
6K=36
K=6
=> A=3*6=18
B=5*3=30
-> A/3=B/5=K
-> A=3K
->B=5K
--> 7*3K-3*5K=36
21K-15K=36
6K=36
K=6
=> A=3*6=18
B=5*3=30
a/b = 3/5
a = 3b/5
7 * 3b/5 - 3b = 36
21b/5 - 3b = 36
21b - 15b = 180
6b = 180
b = 180 : 6
b = 30
a = 3 * 30/5
a = 18
a = 3b/5
7 * 3b/5 - 3b = 36
21b/5 - 3b = 36
21b - 15b = 180
6b = 180
b = 180 : 6
b = 30
a = 3 * 30/5
a = 18