7.2x 8.5-6x=30.5 +1.1x解：61.2-6x=30.5 +1.1x61.2-30.5=1.1x+6x30.7=7.1x7.1x=30.7x=307/71
7.2*8.5-6x=30.5+1.1x7.2*8.5-30.5=6x+1.1x30.7=7.1xx 约等于4.32
