We know that if the slope of a line is m, then the slope of the line that is perpendicular to it would have be; -1/m.
In this question, m = ½
Thus, the slope of the line that is perpendicular to it is; -1/(½) = -2
However, to find the slope of the line parallel to it would mean that the value of m which is the original slope will remain the same. Original slope = ½, thus the only option with slope as ½ is option C where b is parallel with the equation; y = ½x - 1
