def cross_equalibrium(T, I, G, NX, a, b):
    """ The equalibrium for the Keynesian cross where aggregate expenditure equals total production
    Args:
        T (float): Tax
        a (float): Constant consumption, a>0
        b (float): Marginal consumption rate, 0<b<1
        I (float): Investment
        G (float): Public expenditure
        NX (float): Net export
    Returns: 
        Result: Production in equalibrium, Y (float)
    """
    return 1/(1-b) * (I + G + NX + a - b*T)