Q92 / 180 · KCET 2008 · Mathematics
The point $(5,-7)$ lies outside the circle
- Correct answerA$x^{2}+y^{2}-8 x=0$
- B$x^{2}+y^{2}-5 x+7 y=0$
- C$x^{2}+y^{2}-5 x+7 y-1=0$
- D$x^{2}+y^{2}-8 x+7 y-2=0$
Solution
Let $S=x^{2}+y^{2}-8 x$
At point $(5,-7)$
$$
\begin{aligned}
\mathrm{S}=5^{2}+(-7)^{2}-8(5) \\
=& 34>0
\end{aligned}
$$
So, point lies outside the circle.
Hence, option (a) is correct.
Hence, the correct answer is option: 'A'.