Answer to Question #228624 in Geometry for Ulrich

Question

, Given the line r with equations y= x + a

A.     The line y= -x represent a line perpendicular to r

B.     The line x= y + a represent a line perpendicular to r

C.     Th line y=-x + b represent a line parallel to r

D.     The line x + y= a represent a line parallel to r

Answer 1

A. The line y= -x represent a line perpendicular to r

The product of the gradient of perpendicular lines is - 1.