The slope of a line that is parallel to each line whose equation is given

Parallel lines, slope is the same so
1) 3x+8y = 12
8y = -3x + 12
  y = -3/8(x) + 3/2, slope = -3/8

slope of a line that is parallel = -3/8

2)5x+4y = 5
  4y = -5x + 5
    y = -5/4(x) + 5/4; slope is -5/4

slope of a line that is parallel = -5/4

perpendicular, slope is opposite and reciprocal

3)
3x+8y = 11
 8y = -3x + 11
   y = -3/8(x) + 11/8. slope = -3/8
slope of perpendicular line = 8/3

4)
x = -7, slope is undefined
so slope of perpendicular line is 0

5)
3x+2y = 12
2y = -3x + 12
 y = -3/2(x) + 6 ; slope = -3/2

5x - 6y = 8
6y = 4x - 8
  y = 2/3(x) - 4/3; slope is 2/3

slope is opposite and reciprocal, so the equals are perpendicular

6)
3x + y = 5
y = -3x + 5; slope = -3

6x + 2y = -15
2y = -6x - 15 
y = -3x - 7.5; slope = -3

both have slope = -3 so equations are parallel

40 & 50 in the right corner are the complementary angles as when placed in a sum (added together) they make 90°