7*0.9-1.2/0.3-0.2=147
7*0.9-1.2/0.3-0.2=75
7*0.9-1.2/0.3-0.2=47.6
这几个 帮帮忙啊
7x(0.9+1.2)÷(0.3-0.2)=147
(7x0.9+1.2)÷(0.3-0.2)=75
7x[(0.9+1.2)÷0.3-0.2]=47.6