move the red points to fill in the answers to 12-16 (the diagram might take a while to load at first)
For the other problems, it looks like you don't know what a linear pair is.
A linear pair is two angles sharing a side and a line (such as angles 3 and 4 in the diagram), they equal 180. Can you finish the rest of the problems?
I think your main problem is linear pairs. Angles AXB and BXC are a linear pair, after moving the points around, what can you find out about linear pairs?
Tell me if you figure it out
and please, if you quote this, remove the [draw]Point (40,100) [label ('A')]; Point (140,100) [label ('C')]; Point (90,30) [label ('B')]; Line (1,2); Point on object (4,.5) [label ('X')]; Ray (3,5); Angle (1,5,3,30,120,'Angle AXB = '); Angle (2,5,3,30,135,'Angle BXC = '); Calculate (30,150,'AXB + BXC = ','A B +') (8,7);[/draw] from the quote
I see a few errors in 12-16
Notice that (m means "measure of angle"): $\displaystyle m1+m2+m3=180$
Thus: $\displaystyle m1+m2=180-m3$
And that: $\displaystyle m3+m4=180$
Therefore: $\displaystyle m4=180-m3$
Therefore: $\displaystyle m1+m2=m4$
I would use that info to check your answers, I DON'T RECOMMEND USING IT TO FIND THE ANSWER!
Anyway, I'm done for the night so you'll have to check over yourself... Ciao