Question

find the center and radius of the circle: x^2+y^2+10x-14y=-10

Answer 1

we haven't talked about these since the first week of the semester, and yet we are expected to remember it on the final tomorrow...

Answer 2

do u know how to complete the square ?
and general equation of circle ?

Answer 3

have to group the x and y terms together and then complete the square

Answer 4

ah, I do x^2+10x+___ and then the same for the y's and complete both squares?

Answer 5

exactly!

Answer 6

and general equation of circle ?

Answer 7

ok so now I have (x^2+10x+25)+(y^2-14y+49)

Answer 8

whats next?

Answer 9

oh and =-10

Answer 10

the general equation of circle is
\((x-h)^2+(y-k)^2=r^2\)

Answer 11

where h,k is centre and r is radius

Answer 12

bring it in that form

Answer 13

and the constant is not just -10

Answer 14

ah, so I pull the 25 and 49 to the other side?

Answer 15

you added 25 right ?
to balance the equation, you need to subtract 25 also

Answer 16

x^2+y^2+10x-14y + 25 +49 -25 -49=-10

Answer 17

and bring all constants to right side.

Answer 18

ok, I'm following along on paper

Answer 19

could you bring it in this form ?
\((x-h)^2+(y-k)^2=r^2\)

Answer 20

(x+5)^2 +(y-7)^2=64

Answer 21

absolutely correct
so whats h,k = ?

Answer 22

-5,7

Answer 23

radius is 8?

Answer 24

both correct :)

Answer 25

awesome, I vaguely remember how to do it haha. thanks for the refresher

Answer 26

welcome ^_^