解方程

1: 3／8 x－25%x=4 2: x÷4=30% 3: 3x+20%x=112 4: x-40%x=3.6

解: ﹙3／8－25%﹚x=4 x=30%×4 3·2 x=112 60%x=3·6

1／8x =4 x=1.2 x=35 x=6

x=32

5: 14%x-9.1=0.7 6: 75%x-25%x=16 7: x-20%x=44×50% 8: x-10%=18

14%x=9.8 0.5x=160. 0. 8x=22 0.9 x=18

x=70 x=32 x=27.5 x=20

9 :60%x+25=40 10: 2x+30%x=9.2 11: 1÷x=85% 12;40%x-5／12=3／4

0.6x=15 2.3x=9.2 x=1÷0.85 解 ： 0.4 x=3／4+5/12

x=25 x=4 x=20／17 x=7/6÷2/5

x=35/12

13: 2﹙x+7﹚-3.6=20.8 14 :x-5.5=3.5-x 15:160×25%-1.3x=17.9 16: 3/8÷x=4/15÷4/9

解 2﹙x+7﹚=24.4 2x=3.5+5.5 1.3x=40-17.9 3/8÷x=3/5

x+7=12.2 2x=9 1.3x=22.1 x=3/8÷3/5

x=5.2 x=4.5 x=17 x=5/8

17: x÷2/7=7/3÷3/8 18: 3/4 x+1/2 x=45×1/3 19: 0.18×3-2x=0.5 20: 0.6÷35%=1/5÷x

x÷2/7=56/9 1.25x=15 2x=0.54-0.5 1/5÷x=12/7

x=56/9×2/7 x=15÷1.25 x=0.04÷2 x=1/5÷12/7

x=16/9 x=12 x=0.02 x=7/60