11.4 Exercise 21

Identify the graph of each equation as a circle, parabola, ellipse, or hyperbola.

ⓐ $16 x^{2} + 9 y^{2} = 144$ ⓑ $y = 2 x^{2} + 4 x + 6$ ⓒ $x^{2} + y^{2} + 2 x + 6 y + 9 = 0$ ⓓ $4 x^{2} - 16 y^{2} = 64$