Find the center and the radius of the circle with the equation: x2-4x+y2-12y+31=0
2 answers:
Answer:
centre = (2, 6) and radius = 3
Step-by-step explanation:
the equation of a circle in standard form is
(x - h)² + (y - k)² = r²
where (h, k) are the coordinates of the centre and r is the radius
To obtain this form complete the square on both the x and y terms
express the equation as
x² - 4x + y² - 12y = - 31
x² + 2(- 2)x + 4 + y² + 2(- 6)y + 36 = - 31 + 4 + 36
(x - 2)² + (y - 6)² = 9 ← in standard form
with centre = (2, 6) and r = = 3
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