a) 2.4 \cdot 7.4 – 1.7 \cdot 5.6 – 4.3 \cdot 3.1 + 5.3 \cdot 2.8 = 17.76 - 9.52 - 13.33 + 14.84 = 9.75
б) -12.42 : 4.6 - 31.93 : 3.1 + 1.98 : 2.64 + 8.2 \cdot 0.4 = -2.7 - 10.3 + 0.75 + 3.28 = -9
в) 0.37 \cdot 4.5 - 4.5 \cdot (-0.22) + 0.93 \cdot (-3.5) = 1.665 + 0.99 - 3.255 = -0.6
Ответ: а) 9.75; б) -9; в) -0.6