問幾條有關Maths既問題（要式同答案）

建議：你可以用多些括號來使人容易明白呢　=)
1.
2/3 * x + 6 = x
x - 2/3 * x = 6
1/3 * x = 6
x = 18

2.
(2x - 3/4) - [(-3)+(-4)]=6
(2x - 3/4) - (- 3 - 4)=6
(2x - 3/4) - (- 7)=6
(2x - 3/4) + 7=6
2x - 3/4 = - 1
2x = - 1 + 3/4
2x = - 1/4
x = - 1/8

3.
9 - ((4x + (1/5)) /3) = 38 / 5
((4x + (1/5)) /3) = 9 - 38 / 5
(4x + (1/5)) /3 = 7 / 5
(4x + (1/5)) = 7 / 5 * 3
(4x + (1/5)) = 21 / 5
4x = 21 / 5 - 1 / 5
4x = 20 / 5
4x = 4
x = 1

希望解答到你 ^^