Question 545090
you should know that for lines to be perpendicular the product of their slopes should be -1.
for parallel lines their slopes are equal.
therefore you should first rearrange your equations into linear forms that is in the form y=mx+c where m is the slope.
so in a) 9x-12y=17 and 3x-4y=17 the equations are
        -12y=-9x+17 and -4y=-3x+17
          y=3/4x-17/12 and y=3/4x-17/4
       we can there conclude that they are parallel since the slopes are equal that is 3/4.
       b)they are neither since we do not even have the respective slopes.
       c)y=3x+4 and y=-3x-2 are also neither since the slopes are not equal
         that is 3 and -3,and their product is not equal to -1.