This is your hack, the .extend()
method of Sympy's Plot
objects
import sympy as syp
x, y = syp.symbols('x, y')
Eq0 = - 2*x + y**2 - 5
Eq1 = x**3 + syp.sin(y) - 10
p0 = syp.plot_implicit(Eq0, (x, -50, 50), (y, -50, 50), show=False)
p1 = syp.plot_implicit(Eq1, (x, -50, 50), (y, -50, 50), show=False, line_color='r')
p0.extend(p1)
p0.show()