a - b = 50,85
a : b = 5 rest 141
a = 5b + 141
5b + 141 - b = 50,85
4b = - 141 + 50,85
b = - 90,15 : 4
b = - 22,5375
a = 5 * (- 22,5375) + 141
a = - 112,6875 + 141
a = 28,3125
si
b - a = 50,85
b : a = 5 rest 141
b = 5a + 141
5a + 141 - a = 80,85
4a = - 90,15
a = - 22,5375
b = 5 * (- 22,5375) + 141
b = 28,3125