a,2.(x-51)=2.2³+20

2.(x-51)=2.8+20

2.(x-51)=16+20

2.(x-51)=36

x-51=36÷2

x-51=14

x=51+14

x=65

b,450÷(x-19)=50

x-19=450÷50

x-19=9

x=19+9

x=28

c,4.(x-3)=7²-1^10

4.(x-3)=49-1

4.(x-3)=48

x-3=48÷4

x-3=12

x=12+3

x=15

d,135-5(x+4)=35

5(x+4)=135-35

5(x+4)=100

x+4=100÷5

x+4=20

x=20-4

x=16

e,25+3(x-8)=106

3(x-8)=106-25

3(x-8)=81

x-8=81÷3

x-8=27

x=27+8

x=35

f,3².(x+4)-5²=5.2²

9.(x+4)-25=5.4

9.(x+4)-25=20

9.(x+4)=20+25

9.(x+4)=45

x+4=45÷9

x+4=5

x=5-4

x=1

g,(2x-15)÷13+51=8²

(2x-15)÷13+51=72

(2x-15)÷13=72-51

(2x-15)÷13=21

2x-15=21.13

2x-15=273

2x=273+15

2x=288

x=288÷2

x=144

h,x²÷4+5^5÷5³=29

x²÷4+3125÷125=29

x²÷4+3125=29.125

x²÷4+3125=3625

x²÷4=3625-3125

x²÷4=500

x²=500.4

x²=2000

x=1000

i,2012³.(x-612)=2012^10

x-612=2012^10÷2012³

x-612=1³

x-612=1

x=1+612

x=613

k,71+(26-3x)÷5=75

(26-3x)÷5=75-71

(26-3x)÷5=4

26-3x=4.5

26-3x=20

3x=26-20

3x=6

x=6÷3

x=2