Решите систему 6m+5n=15 3m-35n=120

6m  + 5n = 15   3m - 35n = 120   /*(-2) 6m + 5n = 15 - 6m + 70n = - 240 ------------------------------ сложим 5n + 70n = 15 - 240 75n = - 225 n = - 3 m = (120 + 35n)/3 = (120 - 105)/3 = 5