from sympy import *

x1 = Symbol('x1')
x2 = Symbol('x2')
x3 = Symbol('x3')
y1 = Symbol('y1')
y2 = Symbol('y2')
y3 = Symbol('y3')
f = [
    y1+y2+y3-10,
    x1+x2+x3-40,
    2*x1+4*y1-36,
    2*x2+4*y2-36,
]
print(solve(f))