The equation of a circle with centre $$$C$$$ is $$$x^{2}+y^{2}-8 x+4 y-5=0$$$. The point $$$Q$$$ also lies on the circle and $$$P Q$$$ is parallel to the $$$x$$$-axis. Write down the coordinates of $$$Q$$$. ........................................................................................................................................................ ........................................................................................................................................................ ........................................................................................................................................................ ........................................................................................................................................................ ........................................................................................................................................................

Mathematics

IGCSE&ALevel

CAIE

Exam No：9709_s20_qp_12 Year：2020 Question No：11(c)

Answer:

$Q$ has the same coordinate as $P y=2$
$Q$ is as far to the right of $C$ as $P x=3+3+1=7 Q(7,2)$

1.3.3 understand that the equation represents the circle with centre and radius (Including use of the expanded form.)