Răspunsuri

2014-04-12T18:08:11+03:00
M-21=f
m-7=4f
m-7=4(m-21)-7
m-7=4m-84-7
m-3m=-84+7-7
-2m=-84
2m=84
m=42  f=42-21=21

Nu e bine. A doua relatie e m-f = 4 (f-7)
m-7= 4(f-7) *
2014-04-12T18:12:23+03:00
M=f+21
m-7=4(f-7) =>m=4f-28+7
                    m=4f-21

f+21=4f-21
42=3f => f=14              //varsta fiului acum
             m=14+21=35 //varsta mamei acum 


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