import pyomo.environ
from pyomo.core import *

model = ConcreteModel()
model.x_1 = Var(within=NonNegativeReals)
model.x_2 = Var(within=NonNegativeReals)
model.obj = Objective(expr=model.x_1 + 2*model.x_2)
model.con1 = Constraint(expr=3*model.x_1 + 4*model.x_2 >= 1)
model.con2 = Constraint(expr=2*model.x_1 + 5*model.x_2 >= 2)
