They are parallel lines.
Perpendiculat straight lines.
perpendicular
It is not one, but they are two perpendicular lines.
If: 12 = 2y+x then y = -1/2x+6 So: y = 2x+4 and y = -1/2x+6 which means that they are perpendicular lines
it equals 72. just do 12 X 6
it equals 70
12 plus 9 equals 21.
12+12
zero solutions. If you plot these two lines, you will see that they are parallel and do not intersect.
12 + 10 + 11 equals 33
9*12 = 108