Graph and equation

import scipy.optimize as opt
import numpy as np
import matplotlib.pyplot as plt
from math import log


def f(variables) :
    (x,y) = variables

    first_eq = 32.73428 + (35094.08 - 32.73428)/(1 + (x/23.12766)**1.021899)-y
    second_eq = 2.6186666666666683*x + 801.2666666666664 -y
    return [first_eq, second_eq]


solution = opt.fsolve(f, (0.1,1) )
print solution

ax = plt.subplot()
xvalue=[]

global xvalue
num = 200
for i in range(10) :
    if i < 4:
        xvalue.append(num)
        num += 100
    else :
        xvalue.append(num)
        num += 200


x = np.array(xvalue)
xdetails = np.arange(min(x)-1, max(x)+1, .01)
y = np.array([ 3513, 2434, 1809, 1497, 1236, 970, 771, 628, 542, 498])
y1 = np.array([ 1432, 1626, 1847, 2038, 2285, 2791, 3554, 3873, 4471, 5045])
m, c = np.polyfit(x, y1, 1)

#y = 529330.5*x^-0.9458724
#y = 32.73428 + (35094.08 - 32.73428)/(1 + (x/23.12766)^1.021899)
#y = 12.52401 + (3513.033 - 12.52401)/(1 + (x/204.072)^291.157)^0.00332465

plt.plot(x, m*x+c ,label = 'test')
plt.plot(xdetails, 32.73428 + (35094.08 - 32.73428)/(1 + (xdetails/23.12766)**1.021899))
plt.plot(x, y, 'o')
plt.plot(x, y1, 'o')
plt.grid(linestyle='--')
plt.legend()

ax.spines['top'].set_visible(False)
ax.spines['right'].set_visible(False)

plt.title('test')
plt.xlabel('Test', labelpad=10)
plt.ylabel('Test', labelpad=10)
#plt.text(1, -7,'matplotlib', horizontalalignment='left',verticalalignment='center')

plt.show()