if (-2,1) and (3,2) are the vertices of a parallelogram , the equation of diagonal is x+y+1=0 and the length of a side is 6 units . Find the other two vertices of the parallelogram .

since the distance b/w the two given vertices is not 6. this implies that the other side let(x,y) will be 6

thus we can get two conditions

(x+2)² + (y-1)² = 36

&  x+y+1=0

thus by solving these two equations we can get one of the vertices

then the remaining vertices can be evaluated by distance formula or any other method