Question 82377
If the first point is labelled as (X,Y) and the second point is labelled as (X1,Y1)
Then for the first point X = z + q and Y = z
For the second point X1 = z - q and Y1 = z
{{{m = (Y - Y1)/(X - X1)}}}
Substitute the X, Y, X1 and Y1 values into the gradient equation.
{{{m = (z - z)/((z + q) - (z - q))}}} Take (z - q) changes the signs to (-z + q)
{{{m = (0)/(z + q - z + q)}}}
{{{m = (0)/(2q)}}}
ie the slope is zero. The line is parallel to the x axis.