\(x \cdot 12 = 36\), \(x = 36 : 12 = 3\).
\(x - 74 = 45\), \(x = 45 + 74 = 119\).
\(48 : x = 4\), \(x = 48 : 4 = 12\).
\(84 + x = 98\), \(x = 98 - 84 = 14\).
Ответ: 3; 119; 12; 14.