SOLUTION: Find the center(h,k) and r of the circle X^2+y^2+10x-18y+106=49

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Question 1011104: Find the center(h,k) and r of the circle
X^2+y^2+10x-18y+106=49
Found 2 solutions by MathLover1, josgarithmetic:
Answer by MathLover1(20850) About Me  (Show Source):
You can put this solution on YOUR website!
Find the center(h,k) and r of the circle
x%5E2%2By%5E2%2B10x-18y%2B106=49
%28x%5E2%2B10x%29%2B%28y%5E2-18y%29%2B106=49......complete squares
%28x%5E2%2B10x%2Bb%5E2%29-b%5E2%2B%28y%5E2-18y%2Bb%5E2%29-b%5E2%2B106=49
%28x%5E2%2B10x%2B5%5E2%29-5%5E2%2B%28y%5E2-18y%2B9%5E2%29-9%5E2%2B106=49
%28x%2B5%29%5E2-25%2B%28y-9%29%5E2-81%2B106=49
%28x%2B5%29%5E2%2B%28y-9%29%5E2-cross%28106%29%2Bcross%28106%29=49
%28x%2B5%29%5E2%2B%28y-9%29%5E2=7%5E2
so,h=-5,k=9, r=7, and the center is at (-5,9)







Answer by josgarithmetic(39620) About Me  (Show Source):
You can put this solution on YOUR website!
You want THIS kind of form: %28x-h%29%5E2%2B%28y-k%29%5E2=r%5E2.

Start with Completing the Squares for the x and y.
x%5E2%2B10x%2B25%2By%5E2-18y%2B81=49%2B25%2B81
%28x%2B5%29%5E2%2B%28y-9%29%5E2=155

radius r=(155)^(1/2)
Center is (-5,9).