4.5x+3.5x=64 42-7x=17.5 2(x+1.7)=25
①3x+5＝17
②3x+0.2×6＝3.6
③3（16.2﹣x）＝19.2
④6x+1.5×0.7＝1.41
1.5x=7.5 3.6x+2.4x=4.32 5(x-2.8)=30
4(x+0.8)=7.2 9(x-4)=63
