http://hocmai.vn/mod/wiki/view.php?id=18771&page=C%C3%A1c+c%E1%BA%A5p+so+s%C3%A1nh+c%E1%BB%A7a+t%C3%ADnh+t%E1%BB%AB 

 Ban vo day tham khao thu nhe ;)

1. Sang said, "I have already written a letter to my family in Thailand."
    Sang said that he had already written a letter to his family in Thailand.
2. Roeun said, "I have got to pick up my children from school at three  o'clock."
    Roeun said that he had got to pick up her children from school at three o'clock.
3. Cun said, "I am studying English at Long Beach City College."
    Cun said that he was studing English at Long Beach City College.
4. Rosa said, "I should start studying Chinese."
    Rosa said that she should started studying Chinese.
5. Evangelina said, "I can speak, read and write Spanish, English, and    Cambodian."
    Evangelina said that she could speak, read and write Spanish, English and   Cambodian.                                                                                                             6. Carmen said, " I am planning to take a trip to Peru."
     Carmen said that she was planning to take a trip to Peru.
7. Gonzalo said, "I don't like Chinese food."
    Gonzalo said that he didn't like Chinese food.
8. Monica Cheng said, "I may go to the Lakewood Mall after class."
    Monica Cheng said that she might to the Lakewood Mall after class.
9. Jose said, "I have lived in Long Beach for six years."
    Jose said that he had lived in Long Beach for six years.
10. Chanty said, "I want to become a nurse."
      Chanty said that she wanted to became a nurse.
11. Truc said, "I had a nice time at the party."
      Truc said that she had seen a nice time at the part.

5 lần

a)  \(\frac{2x-5}{x+5}=3\)

  \(\Leftrightarrow2x-5=3\left(x+5\right)\)

  \(\Leftrightarrow2x-5=3x+15\)

  \(\Leftrightarrow2x-3x=15+5\)

  \(\Leftrightarrow-x=20\\ \)

   \(\Leftrightarrow x=-20\)

b) \(\frac{x^2-6}{x}=x+\frac{3}{2}\)

  \(\Leftrightarrow\frac{x^2-6}{x}=\frac{2x+3}{2}\)

  \(\Leftrightarrow2\left(x^2-6\right)=x\left(2x+3\right)\)

  \(\Leftrightarrow2x^2-12=2x^2+3x\)

  \(\Leftrightarrow3x=-12\)

  \(\Leftrightarrow x=-4\) 

c) \(\frac{\left(x^2+2x\right)-\left(3x+6\right)}{x-3}=0\)

  \(\Leftrightarrow\frac{x\left(x+2\right)-3\left(x+2\right)}{x-3}=0\)

  \(\Leftrightarrow\frac{\left(x+2\right)\left(x-3\right)}{x-3}=0\)

  \(\Leftrightarrow x+2=0\)

  \(\Leftrightarrow x=-2\)

d)  \(\frac{5}{3x+2}=2x-1\)

 \(\Leftrightarrow5=\left(2x-1\right)\left(3x+2\right)\)

 \(\Leftrightarrow5=6x^2+x-2\)

 \(\Leftrightarrow6x^2+x-7=0\)

 \(\Leftrightarrow\left[\begin{array}{nghiempt}1\\\frac{-7}{6}\end{array}\right.\)

e)  \(\frac{2x-1}{x-1}+1=\frac{1}{x-1}\)

   \(\Leftrightarrow2x-1+x-1=1\)

   \(\Leftrightarrow3x=3\)

   \(\Leftrightarrow x=1\)

g) \(\frac{x+3}{x+1}+\frac{x-2}{x}=2\)

  \(\Leftrightarrow\frac{x\left(x+3\right)}{x\left(x+1\right)}+\frac{\left(x-2\right)\left(x+1\right)}{x\left(x+1\right)}=\frac{2x\left(x+1\right)}{x\left(x+1\right)}\)

  \(\Leftrightarrow x\left(x+3\right)+\left(x-2\right)\left(x+1\right)=2x\left(x+1\right)\)

  \(\Leftrightarrow x^2+3x+x^2-x-2=2x^2+2x\)

  \(\Leftrightarrow2x-2x-2=0\)

  \(\Leftrightarrow-2=0\)    \(\Rightarrow\)Phương trình vô nghiệm 

Căng đây... :((

a, x+y=63       3x=63          x=21                x=21             x=21

    x-2y=0        x+y=63         21+y=63         y=63-21        y=42

Vậy phương trình có nghiệm duy nhất là: x=21

                                                                        y=42

b, 2x+3y=37          10x+15y=185       37y=185          y=5                 y=5

    5x-11y=0            10x-22y=0            5x-11y=0         5x-11*5=0       x=11

Vậy hệ phương trình trên có một cặp nghiệm duy nhất là x=11

                                                                                                  y=5

1, Linda is watching TV in her room now.

2, Mary is going for a walk with Tom right now.

3, What is your father doing at the present?

4, Tony is not revising his lesson at the moment.

5, Mai is writing an English essay at this present.