(3g -4) -2 (3g+4)

To solve the expression (3g -4) -2 (3g+4), let's distribute the -2 to each term inside the parentheses:

(3g - 4) - 2 (3g + 4)

= 3g - 4 - 2 * 3g - 2 * 4

= 3g - 4 - 6g - 8

Now, let's combine like terms:

= (3g - 6g) + (-4 - 8)

= -3g - 12

Therefore, the simplified expression is -3g - 12.