42-...+8=43, ...+1-8=51, ...+6-40=23, 75+4- ...=63, 71 -...+5=76

42 - х + 8 = 43-х = -42 - 8 + 43-х = -7 х = 7Проверка: 42 - 7 + 8 = 43;  35 + 8 = 43;  43 = 43---------------------------------------х + 1 - 8 = 51х = -1 + 8 + 51х = 58Проверка: 58 + 1 - 8 = 51;    51 = 51--------------------------------------х + 6 - 40 = 23х = 23 - 6 + 40х = 57Проверка:57 + 6 - 40 = 23;  63 - 40 = 23;      23=23--------------------------------------75 + 4 - х = 6379 - х = 63х = 79 - 63х = 16Проверка:75 + 4 - 16 = 63;    79 - 16 = 63;    63 = 63----------------------------------------71 - х + 5 = 76-х = 76 - 71 - 5 х = 0Проверка:  71 - 0 + 5 = 76;    76 = 76