In the following equations, what is the equation for a circle? Multiple choice: A. x ^ 2 + y ^ 2 + 2XY + 2x + 2Y + 1 = 0 B. 2x^2+3Y^2=5 C. 4x^2+(2Y-1)^2+4X-1=0 D.(3X-1)^2+9Y^2+12Y+5=0 Please write the details and reasons, thank you

The coefficients of X and y are the same, and there is no XY term
So it's not ab
The formula D is (3x-1) &# 178; + (3Y + 2) &# 178; = - 1
r²=-1

RELATED INFORMATIONS

1. How to express a section of the circle equation For example, x ^ 2 + y ^ 2 = 1, I want to represent the trajectory of a curve in this circle, so the equation of this trajectory is also x ^ 2 + y ^ 2 = 1, but there is a value range, so how to represent this value range?
2. How to find the equation of circle 1. To solve the equation of a circle with radius 1 and center point (4, - 1) 2. Find the equation of the circle passing through the intersection of the straight line x + 3Y + 7 = 0 and 3x-2y-12 = 0, and the center of the circle is point C (- 1,1) 3. Solving the equation of a circle passing through three points o (0,0), m (1,0), n (0,2)
3. The equation of circle A circle is tangent to the y-axis, the center of the circle is on the straight line x-3y = 0, and the chord length obtained by cutting the circle with the straight line y = x is 2 and the root sign is 7
4. The equation of line and circle If the line 3x + 4Y + k = 0 is tangent to the circle (x-3) ^ 2 + y ^ 2 = 4, then the value of K is equal to
5. How to find the equation of a circle symmetric to a line?
6. Detailed steps of matching method and undetermined coefficient method (undetermined coefficient method should have examples) Given the function f (x-1) = x ^ 2-3x + 2, find f (x + 1) Please use the matching method to list the detailed steps, because I don't know how 2 - (x-1) in step f (x + 1) ^ 2 - (x-1) comes from There are also the detailed steps of undetermined coefficient method (please work out an example for me) It's really troublesome. But thank you for 80
7. The main process of applying the method of undetermined coefficient to solve elliptic standard equation is?
8. The general steps of finding the analytic expression of function by undetermined coefficient method Be specific
9. The equation of the circle passing through the point a (0,5) B (1, - 2) C (- 3, - 4) is solved by the method of undetermined coefficient, and D E F is calculated first
10. 1) Try to find the circular equation through three known points （1,1）（2,-1）（3,2） 2) A circle and two parallel lines 2x + y = 5 are tangent to 2x + y + 15 = 0 and pass through point (2,1) Find the equation for this circle 3) A circle passes through (1,1) and (1, - 1) and is tangent to the straight line X - 2 = 0. Find the equation of the circle 4) Try to find the parameter equation of circle x ^ 2 + y ^ 2-x-3y = 0 5) Try to find the circular equation with the diameter of the line between (2, - 5) and (8, - 1), and find the parametric equation of this circle 20 points for answering one question
11. How to express the equation of a circle in space? Know the center coordinate, normal vector and radius length of the circle. How to express the equation of the circle? It's the equation of a circle in three-dimensional coordinates~
12. How to express the equation of circle in plane rectangular coordinate system?
13. The difficult problem of equation of straight line and circle It is known that the circle C satisfies the following three conditions: 1. The chord length obtained by cutting the y-axis is 2. 2. The ratio of the arc length of two arcs divided by the axis is 3:1. 3. The distance between the center of the circle C and the straight line x-2y is 5 / 5. Find the equation of circle C
14. On the equation of line and circle 1. What are the characteristics of the line represented by equation (2x + Y-5) + a (x-7y + 6) = 0 (a ∈ R)? 2. What are the characteristics of the line represented by the equation (a1x + b1y + C1) + a (a2x + b2y + C2) = 0 (a ∈ R, a1x + b1y + C1 = 0 and a2x + b2y + C2 = 0)?
15. The equation of line and circle If the equation of L1 is 3x-y-1 = 0, then the equation of L2 is
16. The equation of line and circle Given the vertex a (3, - 1) of △ ABC, the linear equation of the middle line on the edge AB is 6x + 10y-59 = 0, The equation of bisector line of ∠ B is: x-4y = 10 = 0, the equation of straight line of BC is obtained
17. If | ab | = 8, then the equation of line L is () A. 5x + 12Y + 20 = 0b. 5x-2y + 20 = 0C. 5x + 12Y + 20 = 0 or x + 4 = 0d. 5x-2y + 20 = 0 or x + 4 = 0
18. On the equation of line and circle Given that a = {(x, y) | X-Y + 2 = 0}, B = {(x, y) | (x-t) ^ 2 + (Y-1) ^ 2 = 2}, and a intersection B is not equal to an empty set, then the value range of T is
19. High school mathematics problems - the equation of line and circle The linear equation passing through point P (- 1,2) and parallel to the tangent of curve y = 3x ^ 2-4x + 2 at point (1,1) is?
20. The equation of line and circle in high school mathematics In a triangle, the opposite sides of angle a, angle B and angle c are known to be a, B and C respectively, and a > C > b is an arithmetic sequence, | ab | = 2. The trajectory equation of the vertex is obtained