Question

Write the general equation for the circle that passes through the points (- 5, 0), (0, 4), and (2, 4).

You must include the appropriate sign (+ or -) in your answer. Do not use spaces in your answer.
4x² + 4y² ___x ___y ___ = 0

Answer 1

[tex]4x^2+4y^2+72x-81y+260=0

Explanation:

For the point (-5,0) we have

4*(-5)^2+4*0^2+a*(-5)+b*0+c=0

100-5a+c=0

-5a+c=-100.......(1)

Fro the point (0,4) we have:

4*0^2+4*4^2+a*0+b*4+c=0

64+4b+c=0

4b+c=-64.....(2)

For the point (2,4) we have:

4*4+4*16+2a+4b+c=0

16+64+2a+4b+c=0

2a+4b+c=80.....(3)

(3)-(2):

2a+4b+c-4b-c=80+64

2a=144

a=72

So we have:

-5*72+c=-100

c=260

And from (2) we have

4b+260=-64

b=-81