Ответ:\(1.2x+3.8x-2.7x=(1.2+3.8-2.7)x=2.3x\).\(4.5y-2.3y+1.6y=(4.5-2.3+1.6)y=3.8y\).\(0.72m-0.24m=0.48m\).\(8.3k-4.3k+1.6k=(8.3-4.3+1.6)k=5.6k\).