AAAAAAAAAAAAAAA

First, sorry for bad grammar to see this long comment
 
I solved both questions on the test sheet in this picture. The answer of the 17th question is -2 and the answer of the 18th question is 137. On 18th question, it is hard to figure out the third blank, then I found an answer by putting value 6 into ‘n’.
 
Speaking about the picture on test sheet, it is quite common to see such thing(drawing on test sheet) on such national tests in South Korean art communities because this test gives 100 minutes to complete. If people have some time during the test, some people draws pictures like this.
 
For me, I was usually paying attention to solve such tests, so I couldn’t draw such stuffs and sometimes I didn’t finish the whole questions because I spent most of time to solve the hardest part of the test(mostly 4-scored ones).
 
It has been 4 years since I barely faced such math questions, so it took a lot of time to solve both questions than I was a high school student. But strangely, those are still get used to.

@Background Pony #DA26  
Oh, I see, yeah. Heh, how unfortunate that one of their characters look so similar >.<

@Cirrus Light  
I think it’s not Arabic 4 but some sort of ‘Fill in the answer here’ symbol in Korean. It appears twice in the text in different forms (one of them has an additional stroke) and is also used used in the text below the frame.

I don’t recognize the (k ² + 1), (k ² + 2), … , (4, k) part. Unless it’s maybe talking about finite sums from 0 to 4? Not sure.
 
I’ve taken a lot of calculus but I oddly don’t recognize a lot of it.

@Scigatt  
See? That’s how little I and math understand each other.

@Nightweaver20xx  
Looks more like pre-calc to me; I don’t see a single limit, integral, or differential here.

Korean… advanced calculus? Yep, the only thing I understand in this image is that there’s a pony in it.