import numpy as np
from scipy.optimize import minimize
from scipy.optimize import Bounds


bounds = Bounds([2,10],[5,20])

x0 = np.array([2.5,15])

def objective(x):
    x0 = x[0]
    x1 = x[1]
    return a*x0 + b*x0*x1 - c*x1*x1

res = minimize(objective, x0, method='trust-constr',options={'verbose': 1}, bounds=bounds)