Question

The focus and vertex of a parabola are $(4,5)$ and $(3,6)$. The equation of axis is

• A. $2x-y+3=0$
• B. $2x-y=0$
• C. $2x+y-13=0$
• D. $x+y-9=0$

Answer 1

The correct option is D $x+y-9=0$

Equation of axis of parabola$=$equation of line joining focus and vertex.

Slope$=m=\frac{6-5}{3-4}=-1$

So the equation of the axis is

$y-5=-1\left(x-4\right)\Rightarrow y-5=-x+4\Rightarrow x+y=9\Rightarrow x+y-9=0$