Given the points A(-1;-1) ,B(2;5) ,C(-1;-5/2) and D(
X;-4) andAB perpendicular to CD, determine the value of X
AB has slope (5-(-1))/(2-(-1)) = 2
CD has slope (-5/2-(-4))/(x-(-1)) = (3/2)/(x+1) = 3/(2x+2)
So, we need to have
-(2x+2)/3 = 2
x = -4