3.9*9.8*0.93=(4-0.1)*(10-0.2)*(1-0.07)=(40-1-0.8+0.02)*(1-0.07)=(39-0.78)*(1-0.07)=39-0.78-39*0.07+0.78*0.07=39-0.78-2.73+0.0546=39-3.51+0.0546=39-3.51+0.01+0.0446=35.5446 4.2*1.2-5.2*0.7=4.8+0.24-3.5...