How to factor the expression 24+8y-16w ?

The best thing to do here is to find a common factor in all 3.
24, 8 and 16 all have 8 in common- therefore, this will be outside the bracket 
You then need to divide everything in the equation by 8, to find out what will go inside the bracket.
24/8= 3
8y/8= y
16w/8= 2w
Therefore, these go inside the bracket.
The factorisation os 24+8y-16w is 8(3+y-2w)
Hope this helps :)