Yesterday, I bought some old bowls cheaply in open-air markets     CHEAP

a) \(x\left(x-3\right)-2x+6=0\)

\(x\left(x-3\right)-2\left(x-3\right)=0\)

\(\left(x-2\right)\left(x-3\right)=0\)

\(\Rightarrow x-2=0\) hoặc \(x-3=0\)

\(x=2\) hoặc \(x=3\)

b) \(5\left(x-1\right)-x^2+x=0\)

\(5\left(x-1\right)-x\left(x-1\right)=0\)

\(\left(5-x\right)\left(x-1\right)=0\)

\(\Rightarrow5-x=0\) hoặc \(x-1=0\)

\(x=5\) hoặc \(x=1\)

My grandparents do exercise in their free time             FREEDOM

a) \(3^5.4^5=\left(3.4\right)^5=12^5\)

b) \(8^5.2^3=\left(2^3\right)^5.2^3=2^{15}.2^3=2^{18}\)

c) \(2^7.5^7=\left(2.5\right)^7=10^7\)

d) \(4^{10}.8^{15}=\left(2^2\right)^{10}.\left(2^3\right)^{15}=2^{20}.2^{45}=2^{65}\)

e) \(4^{15}.5^{30}=4^{15}.\left(5^2\right)^{15}=4^{15}.25^{15}=\left(4.25\right)^{15}=100^{15}\)

f) \(9^{12}.3^5=\left(3^2\right)^{12}.3^5=3^{24}.3^5=3^{29}\)

1. A
2. C
3. B
4. D
5. A
6. A
7. C
8. A
9. D
10. A
11. C
12. A
13. C
14. D
15. B
16. A
17. C
18. D
19. B
20. D

1. Let's meet______________front of the theater. (on / at / a bout / in)

2. People often call the school to______________the surboards.  ( buy / come / join / book)

Tom and I are reading comics tonight.

1. C 
2. A 
3. C 
4. B 
5. B 
6. A 
7. D 
8. C 
9. D
10. C

\(9^2-\left[\left(12+10:2\right)-7\right].5\)

\(=81-\left[\left(12+5\right)-7\right].5\)

\(=81-\left[17-7\right].5\)

\(=81-10.5\)

\(=81-50\)

\(=31\)

\(x^2+9y^2+z^2+\dfrac{19}{2}>2x+12y+4z\)

\(\left(x^2-2x+1\right)+\left(9y^2-12y+4\right)+\left(z^2-4z+4\right)+\dfrac{1}{2}>0\)

\(\left(x-1\right)^2+\left(3y-2\right)^2+\left(z-2\right)^2+\dfrac{1}{2}>0\) (luôn đúng)

Ta có: điều phải chứng minh