For what values of the variable is the expression below undefined? 5z+6 / 6z^2-6z. PLEASE HELP!

Matteo makes raspberry punch. the table shows how many parts ginger ale and raspberry juice to use for a batch. raspberry punch parts ginger ale 2 parts raspberry juice 3 matteo decides to add one part of raspberry juice. what is the new ratio of ginger ale to raspberry juice?

In triangle abc segment de is parallel to the side ac . (the endpoints of segment de lie on the sides ab and bc respectively). find de, if ac=20cm, ab=17cm, and bd=11.9cm;

Ineed in figuring out this problem.