Since you that that line is 180 degrees you can simply do 180-149 and find that the answer is 31 degrees. So you would do 13x+5=31, 31-5=26, 26/13, and then x=2 :)
The line segment is translated to the left across the square.
although an image would be useful
The answer would be 198/300. That simplified would be 33/50. If you want a percent, it would be 66%.
3x - y = 10 . . . (1)
-x + y = 12 . . . (2)
(1) + (2) => 2x = 22 => x = 22/2 = 11
From 2, -11 + y = 12 => y = 12 + 11 = 23