The graphs of the two linear equations ax + by = c and bx - ay = c, where a, b and c are all not equal to zero, Choose the correct answer
A) are parallel
B) intersect at one point but not perpendicular
C) intersect at two points
D) perpendicular
E) none of the above
find the slopes of the two lines   a x + b y = c , slope m1 = - a / b   b x - a y = c , slope m2 = b / a   m1*m2 = (- a / b)(b / a) = - 1   The two lines are perpendicular   ANSWER : perpendicular
<result>D</result>
The graphs of the two linear equations ax + by = c and bx - ay = c, where a, b and c are all not equal to zero,