Given equation of parabola is y=x2−2x+5 ......(i) By putting x1=1,x2=3 in Eq. (i), we get y1=4and y2=8 ∴ Points on the parabola are (1,4) and (3,8) Equation of the chord of given parabola by joining the points (1,4) and (3,8) will be y−4=
8−4
3−1
(x−1) y−4=2x−2 ⇒ 2x−y+2=0 Now, equation of tangent parallel to chord will be 2x−y+k=0 ......(ii) In given options, only option (b) satisfies the condition for Eq. (iii) i.e. 2x−y+1=0 ......(iii)