(1−x1) or (y1−2)2=3x12(x1−1) or 2x13−4=3x13−3x12[ As (x1,y1) lies on the curve ] or x13−3x12+4=0 or (x1+1)(x1−2)2=0 ∴x1=−1 or 2 But x1≠=−1 (it is clear from equation (1)) ∴x1=2 ∴y1=2±2√3 Points of contact are (2,2+2√3) and (2,2−2√3) ∴ sum of x -coordinates of points of contact is 4 ∴ sum of y -coordinates of points of contact is 4