Can you help me? This is due soon

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;

Farnesene is a sesquiterpene. how many different isomers arising from double-bond isomerizations are possible? g

Choose a second initial value that is 0.01 greater than the initial value from question 9. iterate it using the function, f, ten times. if necessary, you can round your results to the nearest ten-thousandth.