Im not sure, when in doubt pick C
Your question is very confusing but x=8 so just plug in 8 where you see X
You can use math away it would help!
So basically, you want to show why the two lines (m and n ) are the "same". To show this you would say <4 &<5 are also supplementary because it is the same as <3 & <6. I think this is what the question is asking. To prove this you use the Converse Theorem. Which is what I just showed you with the angles.