Question

equation of circle

Answer 1

\[(x-h)^2+(y-k)^2=r^2 \]
first step
just replace
h with -5
k with -7
The only thing left to determine is the radius
and you know (0,0) is a point on the circle so plug in to find r

Answer 2

if the centre of circle is (-g,-f),then equation of circle :-
\[\large \bf (x+g)^2+(y+f)^2=r^2\]

Answer 3

where (-g,-f)=(-5,-7)

Answer 4

Like this (x-5)^2 + (y - -7)^2 = r^2

Answer 5

well you replace k with -7
but you didn't replace h with -5

Answer 6

see,generalised form of equation of circle :-
\[\large \bf (x-a)^2+(y-b)^2=r^2\]
where,(a,b) is centre of circle

Answer 7

in your question,(-5,-7) is centre.
So,
\[\large \bf (x-(-5))^2+(x-(-7))^2=r^2\]

Answer 8

finally,we get
\[\large \bf (x+5)^2+(y+7)^2=r^2\]

Answer 9

@mayankdevnani I liked your equation too :)

Answer 10

xD

Answer 11

how do I plug in (0,0) to find r?

Answer 12

and it is given that circle is passing through (0,0)
plug this value

Answer 13

replace x with 0 and replace y with 0

Answer 14

and actually you don't really need to find r
just r^2

Answer 15

\[\large \bf (0+5)^2+(y+7)^=r^2\]
\[\large \bf 25+49=r^2\]

Answer 16

so,
\[\large \bf 74=r^2\]

Answer 17

finally,
\[\large \bf (x+5)^2+(y+7)^2=74\]

Answer 18

oh I see so c then

Answer 19

yeah

Answer 20

thanks

Answer 21

welcome :)

Answer 22

for helping me with all of my questions. It's appreciated. :)

Answer 23

:) it's my pleasure !