Answer:
(a) Equation of parallel line is y = x + 4
(b) Equation of perpendicular line is y = - x + 8
Explanation:
Given line is
x - y = 4
Rewrite this as
x - 4 = y
or
y = x - 4
This is the equation of a line in slope intercept form which is generally
y = mx + b
where m is the slope and b the y-intercept
Here m = 1, b = -4
(a) A parallel line will have the same slope but a different y-intercept
So for starters we can write the equation of the parallel line as
y = x + b
Since this passes through (2,6) sub 2 for x and 6 for y to get
6 = 2 + b
==> b = 4
Equation of the line is
y = x + 4
(b) A perpendicular line will have as slope -1/m where m is the slope of the original line
Here m = 1, so -1/m = -1/1 = -1
Equation will be of the form
y = -x + b
Since this also passes through (2,6)
6 = -2 + b
==> b = 6 + 2 = 8
Equation of perpendicular line is
y = -x + 8