0.7x÷0.7=6.3÷0.7

X=9

(79)23.4=2x

2x÷2=23.4÷2

X=11.7

(80)4x-x=48.6

3x=48.6

3x÷3=48.6÷3

X=16.2

(81)4.5x-x=28

3.5x=28

3.5x÷3.5=28÷3.5

X=8

(82）X-5.7=2.15

X=5.7+2.15

X=7.85

（83）5X-2X=18

3x=18

3x÷3=18÷3

X=6

（84）3X+0.7=7

3x+0.7-0.7=7-0.7

3x=6.3

3x÷3=6.3÷3

X=2.1

（85)3.5×2=4.2+x

4.2+x=7

X=7-4.2

X=2.8

(86)26×1.5=2x+10

2x+10=39

2x+10-10=39-10

2x=29

2x÷2=29÷2

X=14.5

(87)0.5×16―16×0.2=4x

4x=4.8

4x÷4=4.8÷4

X=1.2

(88)13 9.25－X=0.403