1) 2.85x+4.6x-3.05x=4.4x
4.4*0.5=2.2
2) 9y-5.96y+7.11y=10.15y
10.15*1.2=12.18
3) 7.325x+3.075x-5.8x=4.6x
4.6*3=13.8
4) 12.654x-4.39y-0.064y=12.654x-4.454y
12.654x-4.454*0.4=12.654x-1.7816
12.654x=1.7816
x=1.7816/12.654≈0.141
12.654*0.141-4.39*0.4-0.064*0.4=0.002614