How do lines 13- 15 the sun has long been set

substitute y = 2x - 4 to x + 2y = 12:

x + 2(2x - 4) = 12     use distributive property

x + (2)(2x) + () = 12

x + 4x - 8 = 12     add 8 to both sides

5x = 20     divide both sides by 5

x = 4

put the value of x to the first equation:

y = 2(4) - 4

y = 8 - 4

y = 4

is there a passage to this question if so plz take a picture

b. our party quickly made its way into the cave / but we failed to find our host [the cyclops] himself inside.

c is the answer because first she would blush to make the reader wonder why which they find out in the next line.