3.5x-0.8x=0.81x(3.5-0.8-0.81)x=0因为3.5-0.8-0.81=1.89>0所以x=0
3.5x-0.8x=0.81x解：3.5x-0.8x-0.81x=0 1.89x=0 x=0
3.5x-0.8x=0.812.7x=0.81x=0.81÷2.7x=0.3
