SOLUTION: Complete the square and write the equation in standard form. Then give the center and radius of the circle. Graph on graph paper. x^2 + y^2 + 2x - 4y - 31 = 0 (x-h)^2 + (y-k)

Algebra ->  Equations -> SOLUTION: Complete the square and write the equation in standard form. Then give the center and radius of the circle. Graph on graph paper. x^2 + y^2 + 2x - 4y - 31 = 0 (x-h)^2 + (y-k)      Log On


   

Question 378272: Complete the square and write the equation in standard form. Then give the center and radius of the circle. Graph on graph paper.
x^2 + y^2 + 2x - 4y - 31 = 0
(x-h)^2 + (y-k)^2 = r^2 Standard form
Center
Radius
Step by step sequence. Thanks.
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
Complete the square in x and y.
x%5E2+%2B+y%5E2+%2B+2x+-+4y+-+31+=+0+
%28x%5E2%2B2x%29%2B%28y%5E2-4y%29-31=0
%28x%5E2%2B2x%2B1%29%2B%28y%5E2-4y%2B4%29-31=1%2B4
%28x%2B1%29%5E2%2B%28y-2%29%5E2=36
%28x%2B1%29%5E2%2B%28y-2%29%5E2=6%5E2
The general equation for a circle centered at (h,k) with a radius R is:
%28x-h%29%5E2%2B%28y-k%29%5E2=R%5E2
Comparing,
Radius:R=6
Center:(h,k)=(-1,2)
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