a)a/b=2/3 rezulta a/2=b/3 si a=2n, b=3n Inlocuim 2n+3n=100 5n=100 n=20 a=40 b=60 b)x=3n, y=4n 2*3n+5*4n/5*4n=6n+20n/20n=26n/20n=26/20=1,3

1) a+b=100 a/b=2/3 a=2b/3 2b/3+b=100 2b+3b=100x3 5b=300 b=300:5 b=60 a+60=100 a=100-60 a=40 2) x/y=3/4 4x=3y 2x=3y/2 (3y/2+5y)/5y=[(3y+10y)/2] / 5y=13y/10y=13/10