a) x + 15 - 8 = 17 → x + 7 = 17 → x = 10,
б) 24 + x - 21 = 10 → x + 3 = 10 → x = 7,
в) 45 - y + 18 = 58 → 63 - y = 58 → y = 5,
г) y - 85 + 12 = 32 → y - 73 = 32 → y = 105,
д) 56 - (x + 12) = 24 → 56 - x - 12 = 24 → 44 - x = 24 → x = 20,
е) 55 - (x - 15) = 30 → 55 - x + 15 = 30 → 70 - x = 30 → x = 40.