Răspuns:
x:y= c rest 5
x<30
5<y<9=>y=6,7,8
Pt. y=6
x:6=c rest 5
x=c×6+5<30=>c=4,3,2,1
x:6=1 rest 5=> x=11
x:6=2 rest 5=> x=17
x:6=3 rest 5=> x=23
x:6=4 rest 5=> x=29
Pt. x=7
x:7=c rest 5
x=7c+5<30=>c=1,23
x:7=1 rest 5=>x=12
x:7=2 rest 5=> x=19
x:7=3 rest 5=> x=26
Pt. x=8
x:8=c rest 5
x=8×c+5<30=>c=1,2,3
x:8=1 rest 5=> x=13
x:8=2 rest 5=> x=21
x:8=3 rest 5=> x=29
x=11,12,13,17,19,21,23,26,29.
Baftă!❤
