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Show that the equation represents a circle by rewriting it in standard form. 3x^2 + 3y^2 + 6x - y = 0 Find the center and radius of the circle. (x, y) = r=

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Final answer:

To rewrite the equation 3x^2 + 3y^2 + 6x - y = 0 in standard form, we group the x terms together and the y terms together, complete the square for x and y, and simplify the equation. The standard form of the equation is (x + 3)^2 + (3y - 1/2)^2 = 81/4. The center of the circle is (-3, 1/6) and the radius is 9/2.

Step-by-step explanation:

To rewrite the equation 3x^2 + 3y^2 + 6x - y = 0 in standard form, we need to complete the square for both the x and y terms. First, let's group the x terms together and the y terms together:

(3x^2 + 6x) + (3y^2 - y) = 0

Now, let's complete the square for x by adding half of the coefficient of x (which is 3) squared to both sides of the equation:

(3x^2 + 6x + 3^2) + (3y^2 - y) = 3^2

Simplifying this gives us:

(x + 3)^2 + (3y^2 - y) = 9

Next, let's complete the square for y by adding half of the coefficient of y (which is -1) squared to both sides of the equation:

(x + 3)^2 + (3y^2 - y + (-1/2)^2) = 9 + (-1/2)^2

Simplifying this gives us:

(x + 3)^2 + (3y - 1/2)^2 = 81/4

Now the equation is in standard form, (x - h)^2 + (y - k)^2 = r^2, where (h, k) is the center of the circle and r is the radius. Therefore, the center of the circle is (-3, 1/6) and the radius is √(81/4), which simplifies to 9/2.

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