Circle And System Of Circles Question 366
Question: If the straight line $ y=mx+c $ touches the circle $ x^{2}+y^{2}-2x-4y+3=0 $ at the point (2, 3), then c =
Options:
- 3
4
5
- 2
Show Answer
Answer:
Correct Answer: C
Solution:
$ y=mx+c $ is a tangent at (2, 3). Equation of tangent at (2, 3) is $ 2x+3y-(x+2)-2(y+3)+3=0 $
$ \Rightarrow 2x+3y-x-2y-2-6+3=0 $
$ \Rightarrow x+y-5=0\Rightarrow c=5 $ .
BETA
