如图，在平面直角坐标系中A点的坐标为（8，y），AB⊥x轴于点B，sin∠OAB=$\frac{4}{5}$，反比例函数y=$\frac{k}{x}$的图象的一支经过AO的中点C，且与AB交于点D．

$3-(\frac{1}{2}+\frac{3}{4})=$ ____

$\frac{1}{2}+(\frac{4}{5}-\frac{7}{10})=$ ____

完形填空。
    Do you know? There is one language 1 in every country in the world. People, young or old, short or tall, thin or fat, use it very often. It is everybody’s second2 . It is very easy to3, though you can't hear it. It is a sign language.
    When you wave(挥手) to a friend on the street, you are 4sign language. When you 5 up your hand in class, you are saying, “Please ask me, I think I know the answer,” or “I have some questions to6.” When you smile at someone, you mean to be 7to him. When you put your forefinger(食指) in front of your mouth, you mean, “8 quiet, please.” When a policeman wants to 9cars or buses, he raises his right arm. Sign language is very useful in quiet places or places 10 of noise. It is different from body language.

有下列方程：①2x+$\frac{x-1}{5}$=10；②x-$\frac{1}{x}=2$；③$\frac{1}{2x+1}-3=0$；④$\frac{2x}{3}+\frac{x-1}{2}$=0．属于分式方程的有（　　）

在最近学校组织的辩论赛上，班级内有两名男生和一名女生参加，女生语言清晰，口齿伶俐，妙语连珠，男生思维敏捷，语言幽默，他们配合默契，优势互补，最终摘取了年级辩论赛的桂冠。