X=139.25-0.403

X=138.847

(89)18.9÷X=0.3

X=18.9÷0.3

X=63

(90)23x=14x＋27

23x-14x=14x-14x+27

9x=27

9x÷9=27÷9

X=3

(91)x＋14x=75

15x=75

15x÷15=75÷15

X=5

(92）95－5x＝80

95-5x+5x=80+5x

5x+80=95

5x+80-80=95-80

5x=15

X=3

（93）1.8+6x＝54

6x=54-1.8

6x=52.2

6x÷6=52.2÷6

X=8.7

（94)6.7x－60.3＝6.7

6.7x=60.3+6.7

6.7x=67

6.7x÷6.7=67÷6.7

X=10

(95)9＋4x＝53

4x=53-9

4x=44

4x÷4=44÷4

X=11

(96)2x+8=16

2x=16-8

2x=8

2x÷2=8÷2

X=4