下列与无机盐的功能无关的是（）

（1）对于S内的所有x和y，f（x+f（y）+xf（y））=y+f（x）+yf（x）；
（2）在区间﹣1＜x＜0与x＞0的每一个内， $\frac{f\left(x\right)}{x}$ 是严格递增的．
求满足上述条件的函数的方程．

    My mother is a diligent and kind woman. She is very busy from morning till night. As a teacher, she works hard.____ Both my brother and I love her dearly as she loves us.

    My mother has been teaching math at a middle school in my hometown. She goes to work early in the morning and does not return home until late in the afternoon. ____ She treats them with patience and teaches them well. For her excellent quality and very good teaching results, she has been elected as a model teacher several times.

    ____ Every day, when she comes back home from work, she sets about doing housework, sweeping the living room and bedrooms or cleaning the furniture, and putting everything in good order. She seems to be busy all the time. As she has been very busy working every day, she looks older than her age. But she looks as cheerful and happy as ever. Mother never buys expensive dresses for herself, but she often buys some inexpensive but high quality clothes for us.____She just eats a plain meal outside when she is too busy to cook herself. She lives a busy yet simple life, without any complaints.

    Often she says to us, “Work while you work, and play while you play. That is the way to be happy and gay. If you do not work, you will become lazy and be of no use to society”. What a piece of good advice this is! ____This advice of hers will always serve as a guide to my behavior. My mother is great indeed, and I always feel proud of her.

A. She enjoys listening to classical music.

B. As a mother, she takes good care of us and gives us every comfort.

C. She loves her students and cares for them.

D. She never goes to expensive restaurants to enjoy meals.

E. My mother is hard-working and never wastes money.

F. I never forget it and always bear it in my mind.

G. Can you tell us something about your mother?