How do you do 43? i'm really confused.

Remove parenthesis on m-2 because you don't need to distribute ( you have an invisible 1, but it won't change the values bc it's a one) Combine your like terms on the side you removed the parenthesis. m-2-5   ->   m-7. Now on  the other side distribute the 2 to the terms in the parenthesis.  once you've done that your equation should look like this 8- 2m +8. now lets look at th full equation. m-7=8-2m+8 move the -2m to the other side, by adding. you now have an equation like this 3m- 7=16. move the -7 to the other side by adding. 3m=23. divide 23 by 3. you're answer should be m= 23/3 
its best to leave your answer as a fraction.  
Hope this helped. (: