SOLUTION: the equations of two circles are x^2 + y^2 - 2x + 4y - 20 = 0 and x^2 + y^2 + 4x - 6y = 0 (a) find the distance between the centres of these circles (b) find the radii of the two

Algebra ->  Finance -> SOLUTION: the equations of two circles are x^2 + y^2 - 2x + 4y - 20 = 0 and x^2 + y^2 + 4x - 6y = 0 (a) find the distance between the centres of these circles (b) find the radii of the two      Log On


   



Question 1124998: the equations of two circles are x^2 + y^2 - 2x + 4y - 20 = 0 and x^2 + y^2 + 4x - 6y = 0
(a) find the distance between the centres of these circles
(b) find the radii of the two circles
(c) determine relationship between the two circle

Answer by rothauserc(4718) About Me  (Show Source):
You can put this solution on YOUR website!
x^2 + y^2 - 2x + 4y - 20 = 0
:
x^2-2x+1 +y^2+4y+4 = 20+5
:
(x-1)^2 +(y+2)^2 = 25
:
center of this circle is (1,-2) and radius is 5
:
x^2 + y^2 + 4x - 6y = 0
:
x^2+4x+4 +y^2-6y+9 = 13
:
(x+2)^2 +(y-3)^2 = 13
:
center of this circle is (-2,3) and radius is square root(13) = 3.6056
:
a) distance = square root( (-2-1)^2 + (3-(-2))^2 ) = 5.831
:
b) radii are 5 and 3.6056
:
c) the given circles intersect at two points
: