As (4,−3) and (4,−1) lie on the line x=4, the axis of the parabola in the line x=4. Distance between focus and vertex ‌=√(4−4)2+(−1+3)2 ⇒a‌=2 Equation of parabola ‌(x−4)2=−4a(y+1) ⇒x2+16−8x=−8(y+1) ⇒x2+16−8x+8y+8=0 ⇒x2−8x+8y+24=0