Respuesta :

6)
3x+15 = 75
3x = 60
x = 20
answer is B.
7)
x = 1/2(x - 9 + 2x - 3)
x = 1/2(3x -12)
x = 3/2x - 6
x = 1.5x - 6
-0.5x = -6
      x = 12
answer is D

8)
3x+5 = 4x - 40
4x - 3x = 5+40
x = 45
answer is A
6.) 20

7.) not sure, i think d

8.) a