Câu trả lời:

a) 8x - 8 -4 = 6x +12 -2
8x - 6x = 10 + 4
2x = 14
x = 7

b) \(\dfrac{15x}{30}\) - \(\dfrac{10\left(2x+1\right)}{30}\) = \(\dfrac{6\left(2x-1\right)}{30}\)
15x - 20x - 10 = 12x - 6
-5x -12x = 10 - 6
-17x =4
x = -4/17