需求价格弹性-弧弹性

def solve(____):
    delta_q = q2 - q1
    delta_p = p2 - p1
    avg_p = (____) / ____
    avg_q = (____) / ____
    elasticity = -(____) * (____)
    return {"____": (____), "____": (____), "____": round(____)}