Răspuns :
a=3b+7
3b+7+b=631
4b=631-7
4b=624
b=624:4
b=156 =>a=631-156 =>a=475
3b+7+b=631
4b=631-7
4b=624
b=624:4
b=156 =>a=631-156 =>a=475
a+b=631
a:b=3 rest 7 => a=3b+7
3b+7+b=631
4b+7=631
4b=631-7
4b=624
b=624:4
b=156
a=3×156+7
a=475
a:b=3 rest 7 => a=3b+7
3b+7+b=631
4b+7=631
4b=631-7
4b=624
b=624:4
b=156
a=3×156+7
a=475