Help me, please D:
It's for a test

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;

Whats the name of the vertical axis

Identify the initial amount a and the growth factor b in the exponential function. a(x)=680*4.3^x