1).Find the co-ordinates of the point A on the line x= -3 such that the line joining A to B(5,3) is perpendicular to the line 2x+5y =12. 2). Using the vertices A(2a,2b), B(-2c, 0), C(2c,0). (i) prove that the medians of a triangle are concurrent. (a median is a line joining a vertex to a midpoint of the opposite sides; the lines are concurrent if they have a common point of intersection); (ii) show that the centroid is 2a/3, 2b/3. (a centroid is the point of intersection of the medians).