Answer :

Answer:

C(3,-4), r=4*sqrt(2)

Step-by-step explanation:

C(p, q)

x^2+y^2+dx+ey+f=0

p=-d/2, q=-e/2, r^2=p^2+q^2-f

x^2+y^2 - 6x+8y-7=0

p=-(-6)/2=6/2=3

q=-8/2=-4

r^2=3^2 +(-4)^2+7

r^2=9+16+7

r^2=32

r=sqrt(32)

r=sqrt(16*2)

r=4*sqrt(2)