(3g - 4) - (3g + 4)

To simplify the expression (3g - 4) - (3g + 4), we can distribute the negative sign to both terms inside the second parentheses:

(3g - 4) - (3g + 4)
= 3g -4 -3g -4

Next, we can combine like terms:
(3g - 3g) + (-4 -4)
= 0g - 8
= -8

Therefore, (3g - 4) - (3g + 4) simplifies to -8.