Help me please? i needa help. am bad at maths.

What is not true about kl and mn? what is mn? (show your work)

Can someone me with #s 8, 9, and 11. with just one of the three also works. prove using only trig identities.

Atrain leaves little? rock, arkansas, and travels north at 90 kilometers per hour. another train leaves at the same time and travels south at 80 kilometers per hour. how long will it take before they are 680 kilometers? apart?