Question 84821
equations are 4x+4y =-4.....................(1)
    and 4x-4y=0...........(2)
 so we can write the equation (1) as 4y = -4x -4
                                  or y = -x -1               

       so the slope is -1 

    (2) we can write as 4y = 4x
                      or y=x

      slope =1
product of these 2 slope is (-1)(1) = -1
 so they r perpendicular to each other
and your ans is ABSOLUTELY correct