III. Collect these mistakes sentences:
1. Are your parents going to buy a new house? ...
2. When is he going to visit London? -Next Sunday ...
3. It's very cloudy. It''s go to rain. ...
4. My sister and I am going to visit our grandqarents in the country this Friday. ... 5. Lily and Windy is going to buy some rice, coffee and beef. ...
6. My brother isn't go to do the housework this weekend. ...
7. Ms. Lisa is going for the zoo. ...

IV. Put the verbs in brackets in the "near future" or the "be going to".
1. Next summer, I _ ti London. My brother lives there and he bought me a plane ticket for my birthday. (travel)
2. Are you going to the cinema? Wait for me. I _ with you! (go)
3. What _ you _ (do) tomorrow? I _ (visit) my grandmother.
4. Jackson, those bags seem quite heavy. I _ you carry them. (help)
5. Jennie _ 15 next Monday. (be)
6. Look at those black clouds. I think it _ . (rain)
7. Be careful! That tree _ (fall)
8. Bye Bye Thomas. I _ you when I arrive home! (phone)
9. What a beautiful girl! I _ her out next Sunday! (ask)

Viết các biểu thức sau dưới dạng lập phương của một tổng hoặc một hiệu: 
a) -x³ + 3x² - 3x + 1            b) 8 - 12x + 6x² - x³ 
c) x³ + x² + x +\(\dfrac{1}{27}\)              d) 8x³ + 12x² + 6x + 1
e) x³ - 6x²y + 12xy² - 8y³   f) x² + \(\dfrac{3}{2}\)x² + \(\dfrac{3}{4}\)x + \(\dfrac{1}{8}\)

Tổng/Hiệu hai đẳng thức: 
1) x^3 + 8 = ?
2) a^3 + 27 = ?
3) y^3 + 125 = ?
4) x^3 - 8 = ?
5) x^3 - 1 = ?
6) x^3 - 27 = ?
7) m^3 - 8 = ?
8) 8a^3 - 27 = ?
9) 27x^3 - 1 = ? 
10) 8m^3 + 1 = ?
11) x^3 + 1/8 = ?
12) m^3 + 27n^3 = ?

a)     A = -3x(x-5) +3( x² -4x) -3x-10
b)     B = 4x( x² -7x +2) – 4( x³ -7x² +2x -5)
c)     C = 5x( x² – x) – x²( 5x-5) -15
d)     D = 7( x² -5x+3)- x( 7x-35) -14
e)     E = x² - 4x - x( x-4) -15

a)3(5x - 1) –x (x- 2) +x² -13x =7
b)1/5x(10x - 15) - 2x(x - 5) = 12

Tính đơn thức M: 2x^6yz^2 - 3x^6yz^2 + M= 5x^6yz^2 + x^6yz^2

Cho tam giác ABC vuông tại B. Tính độ dài AB biết  
AC= 12cm, BC= 8cm