1)... a=M₅+4 |+1 => a+1=M₅ ;
a=M₈+7 |+1 => a+1=M8 ;
a=M₁₀+9 |+1 => a+1=M₁₀ ;
c.m.m.m.c.[5;8;10]=40
=> a(minim)=40-1=39 ;
Proba: 39:5=7 (rest 4) ; 39:8=4 (rest 7) si 39:10=3 (rest 9) .
2)... 2xy-5y=7 ⇔ y(2x-5) = 7 = 1*7 = 7*1
pt. y=1 ⇒ 2x-5=7 adica: x=6 ;
pt. y=7 ⇒ 2x-5=1 adica: x=3 ;