Răspunsuri

2014-02-23T09:24:01+02:00


a + b = 21 => a = 21 - b

a - b = 1/3b (inlocuim)

21 - b - b = 1/3b (aducem la acelasi numitor comun)

63 - 6b = b

7b = 63

b = 9 => a = 21 - 9 = 12



  • Utilizator Brainly
2014-02-23T10:03:54+02:00
X+y=21
x-y=1/3*y x=1/3*y+y=4/3*y

4/3*y+y=21
7/3*y=21
y=9
x=21-9=12