7χ－2×9＝806x－4x＝20.2（χ+12）÷4＝4.5

解:7x-18=80解:2x=20.2解:(x+12)/4*4=4.5*4

7x-18+18=80-+182x/2=20.2/2x+12=18

x=98x=10.1x+12-12=18-12

x=6

6x－0.4×6=9.64x＋80=160

解:6x-2.4=9.6解:4x+80-80=160-80

6x-2.4+2.4=9.6+2.44x=80

6x=124x/4=80/4

x=2x=20

x-8.2＝4.48x＝32

解：x＝4.4+8.2解:x＝32÷8

8x=32

解；x=32/8

x=4

4x=4,x=1

4x=8,x=2

4x=12,x=3

4x=16,x=4

4x=20,x=5

4x=24,x=6

4x=28,x=7

4x=32,x=8

4x=36,x=9

4x=40,x=10

4x=44,x=11

4x=48,x=12

4x=52,x=13

4x=56,x=14

4x=60,x=15

4x=64,x=16

4x=68,x=17

4x=72,x=18

4x=76,x=19

4x=80,x=20