Răspunsuri

2014-11-03T15:26:09+02:00
A-b = 21/5     a= 21/5+b    a= (21+5b) / 5
a=2b/5 

(21 + 5 b)/5 = 2b/5
21+5b=2b
3b= -21
b= -7
a =  -14/5 = - 2 4/5

verificare

a-b = -14/5 -(-7) = -14/5 +7 = -14/5 +35/5 = - 21/5