17x2−16|x|y+17y2=225
import numpy as np
import matplotlib.pyplot as plt
x = np.arange(-5, 5, .01)
y = np.arange(-5, 5, .01)
x, y = np.meshgrid(x, y)
f = 17*x**2 - 16*np.abs(x)*y + 17*y**2 - 255
plt.figure()
plt.contour(x, y, f, 0, colors='red')
plt.title(r'$17x^2-16\left|x\right|y+17y^2=225$')
plt.show()