x² + 2x + y2 - 6y =-6
Mathematics · High School · Thu Feb 04 2021
Answered on
Let's solve the equation step by step and rewrite it in a way that makes it easy to identify its geometric representation. The given equation is:
x² + 2x + y² - 6y = -6
To solve this equation, we need to complete the square for both the x-terms and the y-terms. This process will allow us to rewrite the equation in the form of a circle equation.
First, let's complete the square for the x-terms:
x² + 2x needs the addition of (2/2)² = 1² = 1 to complete the square.
So we add 1 to both sides:
x² + 2x + 1 + y² - 6y = -6 + 1
Now, the equation becomes:
(x + 1)² + y² - 6y = -5
Next, we complete the square for the y-terms:
y² - 6y needs the addition of (6/2)² = 3² = 9 to complete the square.
So we add 9 to both sides:
(x + 1)² + y² - 6y + 9 = -5 + 9
This gives us:
(x + 1)² + (y - 3)² = 4
Now the equation is in the standard form of a circle:
(x - h)² + (y - k)² = r²
Where (h,k) is the center of the circle and r is the radius.
Comparing, we have h = -1, k = 3, and r² = 4. Thus the radius r is √4 = 2.
The equation represents a circle with center at (-1, 3) and radius 2.