Respuesta :
Add the common like terms but first seperate them and the pair them
You have to factor by grouping. so break it down and find the gcf between 15 and 20 and then find the gcf between 6 and 8 so you should get -5c(-3w+4z)2d(-3w+4z) and your final answer should be (-5c+2d)(-3w+4z)