Question

a+b=30,a+c=40,b+c=50afla a, b si c știind că a+b=30. a+c=40,b+c=50

Answer 1

a+b=30
a+c=40
b+c=50
___________le adunam cele 3 relatii
2a+2b+2c=120
2(a+b+c)=120
a+b+c=120:2
a+b+c=60
inlocuim30+c=60  =>c=60-30
                                     c=30
40+b=60
b=20
a+30+20=60
a=10

Answer 2

2 (a+b+c)=30 +40 +50
2 (a+b+c)=120
a+b+c=120÷2=60
a+b+c=60
30+c=60 c=60 -30=30
40 +b=60 b=60-40 =20
50+a=60 a=60 -50 a=10
10 +20 +30 =60