Bom dia, estou tomando as underlines como sendo o sinal de menos ( - ), sendo assim,

D) 2(3x-10) = x+5

6x-20 = x+5

6x-x = 5+20

5x = 25

x = 25/5

"x = 5"

E) 4(x-5) = 10-x

4x-20 = 10-x

4x+x = 10+20

5x = 30

x = 30/5

"x = 6"

F) 2(x-3) = x

 2x-6 = x

 2x-x = 6

"x = 6"

G) 2(x+10) = x

 2x+20 = x

 2x-x = -20

"x = -20"

H) 3(x-5) = x+5

 3x-15 = x+5

3x-x = 5+15

 2x = 20

x = 20/2

"x = 10"

I) 2(x+7) = x+3

 2x+14 = x+3

 2x-x = 3-14

 "x = -11"

J) 2(x+5) = x-1

2x+10 = x-1

 2x-x = -1-10

"x = -11"