Răspuns:
ab:(a+b)=6r1
ab=6(a+b)+1
ab=6a+6b+1
10a+b=6a+6b+1
10a-6a=6b-b+1
4a=5b+1
4a-nr par
5b,1-nr impar=>b=nr impar(1,3,5,7,9)
inlocuim
b=1 avem 4a=5·1+1 nu convine
b=3 avem 4a=5·3+1=>4a=16=>a=16:4=>a=4 convine
b=5 avem 4a=5·5+1 nu convine
b=7 avem 4a=5·7+1 =>4a=36=>a=36:4=>a=9 convine
b=9 avem 4a=5·9+1 nu convine
ab=43
ab=97
V:
43:(4+3)=43:7=6 r 1 (A)
97:(9+7)=97:16=6 r 1 (A)
