Question

Which is an equation of a circle with center (-5, -7) that passes through the point (0, 0)?

A.) (x + 5)2 + (y + 7)2 = 74
B.) (x + 5)2 + (y + 7)2 = 37
C.) (x - 5)2 + (y - 7)2 = 37
D.) (x - 5)2 + (y - 7)2 = 74

Answer 1

if it passes through origin, that means the distance between (-5, -7) and (0,0) is the radius. the rest is plugging the center of the circle into the equation of a circle

Answer 2

well the standard form of a circle is

\[(x - h)^2 + (y - k)^2 = r^2\]

(h, k) is the centre... so you should be able to match the information...

you will need to find the distance from the centre (-5, -7) to the point (0,0) to find the radius....

hope it helps

Answer 3

8.6 is the distance

Answer 4

so what is 8.6^2...?

Answer 5

73.96

Answer 6

so which answer contains your centre and radius

Answer 7

this are my answer choices :

A.) (x + 5)2 + (y + 7)2 = 74
B.) (x + 5)2 + (y + 7)2 = 37
C.) (x - 5)2 + (y - 7)2 = 37
D.) (x - 5)2 + (y - 7)2 = 74

Answer 8

and im thinking its either A or D

Answer 9

ok... so the centre is (-5, -7)

and the general form is

\[(x - h)^2 + (y - k)^2 = r^2\]

(h, k) is the centre and r is the radius...

so when you substitute your radius it will be 74

so which equation A or D has the correct centre information..?

Answer 10

D ?

Answer 11

close.... no its A

subsitute -5 and its (x - (-5))^2 = (x + 5)^2

Answer 12

thanks :)