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

To solve this expression, we can simplify by applying the distributive property and combining like terms.

First, let's distribute the '-2' to both terms in the parentheses:
-2(3g + 4) = -2*3g + (-2)*4 = -6g - 8

Now, let's simplify the term (3g - 4):
3g - 4

Putting it all together, the expression becomes:
(3g - 4) - 2(3g + 4) = (3g - 4) - (6g + 8)

Now, let's simplify by removing the parentheses:
= 3g - 4 - 6g - 8

Next, let's group the like terms:
= (3g - 6g) + (-4 - 8)

Simplifying further:
= -3g - 12

Therefore, the simplified form of (3g - 4) - 2(3g + 4) is -3g - 12.