Patrick B. answered 05/07/20
Math and computer tutor/teacher
x = -y^2 this parabola opens to the left
The second equation is an ellipse:
x^2 - (1/13) y^2 + (2/13) y = -12/13
x^2 - (1/13) [ y^2 + 2 y ] =12/13
x^2 - (1/13) [ y^2 + 2y + 1] = 12/13 -1/13 <--- completes the square
x^2 - (1/13] (y +1)^2 = 11/13
x^2 - (y+1)^2/13 = 11/13
the ellipse has center at (0, -1)
the horizontal radius is 1
the vertical radius is sqrt(1/13) = sqrt(13)/13