Ответ:\(15-14.26-6:12.5=15-14.26-0.48=0.26\).\(58.78-1.38\cdot(275.4:6.8)=58.78-1.38\cdot40.5=58.78-55.89=2.89\).Ответ: а) \(0.26\); б) \(2.89\).