Explanation:
what should be the result ?
all I can see are very simple expressions, but with no way to e.g. solve them to a single number or do something else specifically.
so, all I can do is resolve brackets and such.
6. -(x+4) = -x - 4
8. 7a(3b - 2c + 4) = 21ab - 14ac + 28a
10. 2/3 (1/4 x - 6) = 2/12 x - 6×2/3 = 1/6 x - 2×2 = 1/6 x - 4