Question

Determine the radius of the circle 4x² + 4y² - 12x = -5

a) 1
b) -5
c) -4
d) 2​

Answer 1

Answer:

given circle is

4x*2+4y*2-12x=-5

=>4x*2+4y*2-12x+5=0

divide with 4

=>x*2+y*2-3x+(5/4)=0

compare with the general equation of circle

2u=-3

u=-3/2

formula for radius of circle r=sqrt(u*2+v*2+w*2-d)

here u we have

v=0

w=0

d=5/4

r=sqrt((-3/2)*2-(5/4))

=sqrt((9/4)-(5/4))

=sqrt(4/4)

=sqrt(1)

=1

radius of given circle r=1