Identify the conic: 16x2 + 9y2 – 36y – 108 = 0

A. Ellipse
Correct! Both squared variables have different positive coefficients. That fact means that this equation represents an ellipse.

B. Circle
Incorrect. The coefficients for the x squared term and the y squared term must be the same to have a circle. These coefficients are different.

C. Hyperbola
Incorrect. One of the coefficients for the x squared term and the y squared term must be negative to have a hyperbola. These coefficients are both positive.

D. Parabola
Incorrect. There can only be one squared variable to have a parabola. This equation contains both an x squared term and a y squared term.


Identify the conic: x2 + 4x + y2 – 2y + 5 = 0

A. Ellipse
Incorrect. In an ellipse, both squared variables have different positive coefficients. In this equation, both squared variables have the same coefficient.

B. Circle
Correct! The coefficients for the x squared term and the y squared term are the same so this equation is a circle.

C. Hyperbola
Incorrect. One of the coefficients for the x squared term and the y squared term must be negative to have a hyperbola. These coefficients are both positive.

D. Parabola
Incorrect. There can only be one squared variable to have a parabola. This equation contains both an x squared term and a y squared term.


Identify the conic: 9x2 - 9y2 + 36x – 45 = 0

A. Ellipse
Incorrect. For an ellipse, both squared variables have positive coefficients. In this equation, the squared variables have opposite signs.

B. Circle
Incorrect. For a circle, both squared variables have positive coefficients. In this equation, the squared variables have opposite signs.

C. Hyperbola
Correct! One of the coefficients for the x2 term and the y2term must be negative to have a hyperbola. This event happens here because y2 has a negative coefficient.

D. Parabola
Incorrect. There can only be one squared variable to have a parabola. This equation contains both an x squared term and a y squared term.


Identify the conic 4y2 – 8y + 3x – 16 = 0

A. Ellipse
Incorrect. For an ellipse, both variables must have a squared term. In this equation, there is no x2 term.

B. Circle
Incorrect. For a circle, both variables must have a squared term. In this equation, there is no x2 term.

C. Hyperbola
Incorrect. For a hyperbola, both variables must have a squared term. In this equation, there is no x2 term.

D. Parabola
Correct! There can only be one squared variable to have a parabola and this equation contains only a y2 term.