Respuesta :

znk

Answer:

(x + 3)² + (y+ 2)² = 1²

Step-by-step explanation:

The standard form for the equation of a circle with centre (a, b) and radius r is

(x - a)² + (y - b)² = r²

x² + 6x + y² + 4y + 12 =  0

Step 1. Subtract the constant from each side

x² + 6x +           y² + 4y        = -12

Step 2. Complete the squares for x and y

Square half the coefficients of x and y

(x² + 6x + 3²) + (y² + 4y + 2²) = -12 + 3² + 2²

Step 3. Write the lhs as squares of binomials

(x + 3)² + (y+ 2)² = -12 + 3² + 2²

Step 4. Convert the rhs to a square

(x + 3)² + (y+ 2)² = -12 + 9 + 4

(x + 3)² + (y+ 2)² = 1

(x + 3)² + (y+ 2)² = 1²

The graph below shows that this is the equation for a circle with

centre (-3, -2) and radius 1.

Ver imagen znk

The center and radius of the given circle are respectively; (-3, -2) and 1

What is the radius of the circle?

The standard form for the equation of a circle with it's centre coordinate (a, b) and radius r is given as;

(x - a)² + (y - b)² = r²

Now, we are given the circle equation to be; x² + 6x + y² + 4y + 12 =  0

Let us subtract 12 from both sides to leave only the variables on the left side;

x² + 6x + y² + 4y + 12 - 12 =  0 - 12

x² + 6x + y² + 4y = -12

Now let us complete the squares for variable x and y;

Square half the coefficients of x and y and add to both the x, y and constant to get;

(x² + 6x + 3²) + (y² + 4y + 2²) = -12 + 3² + 2²

(x² + 6x + 3²) + (y² + 4y + 2²) = -12 + 9 + 4

(x² + 6x + 3²) + (y² + 4y + 2²) = 1

Write the left hand side as squares of binomial to get;

(x + 3)² + (y+ 2)² = 1

This can be also written as;

(x + 3)² + (y+ 2)² = 1²

Thus, from the general standard form of equation of a circle, we can say that;

centre is at (-3, -2) and radius is 1.

Read more about radius of a circle at;https://brainly.com/question/14283575

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