Răspuns :
Răspuns:
(5a+4b)/(5a+7b)=2/3
3(5a+4b)=2(5a+7b)
15a+12b=10a+14b
5a=2b b=5a/2 ⇒b²=25a²/4
(b²-a²)/(2a²-3ab+b²)
(25a²/4-a²)/(2a²-3a×5a/2+25a²/4)=
=[(25a²-4a²)/4]/[(8a²-30a²+25a²)/4]=
=(21a²/4)/(3a²/4)=
=21a²/4 × 4/3a²=7
Sper ca te-am ajutat!
Răspuns:
(5a+4b)/(5a+7b)=2/3
3(5a+4b)=2(5a+7b)
15a+12b=10a+14b
5a=2b b=5a/2 ⇒b²=25a²/4
(b²-a²)/(2a²-3ab+b²)
(25a²/4-a²)/(2a²-3a×5a/2+25a²/4)=
=[(25a²-4a²)/4]/[(8a²-30a²+25a²)/4]=
=(21a²/4)/(3a²/4)=
=21a²/4 × 4/3a²=7
Sper ca te-am ajutat!