Given, vertex of the parabola (h,k)=(−1,1) and its focus is (a+h,k)=(2,1)‌ or ‌a+h=2⇒a=3 We know that as the y-coordinate of vertex and focus are same,therefore axis of parabola is parallel to X-axis. Thus, equation of parabola is (y−k)2=4a(x−h) (y−1)2=4×3(x+1) (y−1)2=12x+12 y2+1−2y=12x+12 y2−12x−2y−11=0