3. C
4. C

10. A
11. A

a) 864 ; 357 ; 756 ; 1248 ; 6390
b) 864 ; 756 ; 6390
c) 357 ; 1248

Uk ko có j

\(a,\left(3^5\cdot3^7\right):3^{10}+5\cdot2^4-7^3:7\)                    \(b,3^2\cdot\left[\left(5^2-3\right):11\right]-2^4+2\cdot10^3\)
\(=3^{12}:3^{10}+5\cdot16-7^2\)                                    \(=9\cdot\left[22:11\right]-16+2000\)
\(=9+90-49\)                                                     \(=9\cdot2-2016\)
\(=50\)                                                                       \(=18-2016=-1998\)
\(c,\left(6^{2007}-6^{2006}\right):6^{2006}\)                                   \(d,\left(5^{2001}-5^{2000}\right):5^{2000}\)
\(=6^{2007}:6^{2006}-6^{2006}:6^{2006}\)                            \(=5^{2001}:5^{2000}-5^{2000}:5^{2000}\)
\(=6-1\)                                                                 \(=5-1\)
\(=5\)                                                                         \(=4\)
\(e,\left(7^{2005}+7^{2004}\right):7^{2004}\)                                   \(f,\left(5^7+7^5\right)\cdot\left(6^8+8^6\right)\cdot\left(2^4-4^2\right)\)
\(=7^{2005}:7^{2004}+7^{2004}:7^{2004}\)                               \(=\left(5^7+7^5\right)\cdot\left(6^8+8^6\right)\cdot\left(16-16\right)\)
\(=7+1\)                                                                    \(=\left(5^7+7^5\right)\cdot\left(6^8+8^6\right)\cdot0\)
\(=8\)                                                                           \(=0\)
\(g,\left(7^5+7^9\right)\cdot\left(5^4+5^6\right)\cdot\left(3^3\cdot3-9^2\right)\)               \(h,\left[\left(5^2\cdot2^3-7^2\cdot2\right):2\right]\cdot6-7\cdot2^5\)
\(=\left(7^5+7^9\right)\cdot\left(5^4+5^6\right)\cdot\left(81-81\right)\)                    \(=\left[\left(25\cdot8-49\cdot2\right):2\right]\cdot6-7\cdot32\)
\(=\left(7^5+7^9\right)\cdot\left(5^4+5^6\right)\cdot0\)                                   \(=\left[\left(200-98\right):2\right]\cdot6-224\)
\(=0\)                                                                         \(=\left[102:2\right]\cdot6-224\)
                                                                                \(=51\cdot6-224\)
                                                                                \(=306-224\)
                                                                                \(=82\)

1/ stop 
2/ wait - calls
3/ will let 
4/ arrives
5/ will help - finishes
6/ do you want - finishes
7/ gets
8/ will go 
9/ will come
10/ will send - leaves

Change the sentences into other forms (affirmative, negative or interrogative forms).

1. Do Phong, Duy and Vy usually walk to school?

+  Phong, Duy and Vy usually walk to school.

-  Phong, Duy and Vy usually don't walk to school. 

2. Kelvin rarely reviews the lesson in the morning.

-   Kelvin rarely doesn't review the lesson in the morning.

?  Does Kelvin rarely review the lesson in the morning?

3. Are Gwen and Anna normally busy on Fridays?

+   Gwen and Anna are normally busy on Fridays.

-   Gwen and Anna aren't normally busy on Fridays.

4. The streets are always crowded at this time of the day.

-   The streets aren't always crowded at this time of the day.

?  Are the streets always crowded at this time of the day?

5. The children seldom have beefsteak for lunch.

-   The children seldom don't have beefsteak for lunch.

?  Do the children seldom have beefsteak for lunch?

6. They don’t often do exercise at the weekends.

+  They often do exercise at the weekends.

?  Do they often do exercise at the weekends?

7. I sometimes forget to turn off the lights before leaving the room.

-   I sometime don't forget to turn off the lights befores leaving the room.

?  Do you sometimes forget to turn off the lights before leaving the room?

+  The canteen frequently run out of drinking water.

?  Does the canteen frequently run out of drinking water?

35. A
36. D
37. C
38. B
39. D
40. A