How do I simplify 3(2a-8b)

You would have to do distribution. So you would have to multiply 3 by 2a and multiply 3 by -8b. 3 times 2a equals 6a (always keep the letter) and 3 times -8b equals -24b. (if there is only one negative number when multiplying, always keep the negative sign.) now you are left with 6a-24b. and since we cant put a into b, your answer would be 6a-24b. hopefully this helped you and sorry if it confused you

Well All you have to do is Just divide the 8 by the 4 and you get 2a-2b 
Unless it's all over 4, if it is, you should have written it as (2a-8b)/4. The parentheses make a difference. ^ ^
If it is all over 4 you can rewrite it as (2a/4)-(8b/4) 
(2/4)a-(8/4)b 
(1/2)a-2b or (a/2)-2b 

Hope I helped :D