1 000 000 002

7,05 metres is 705 centimetres

31126326 nha 

k cho mình đi

\(\left(2^{m+1}+1\right)\left(2^m+1\right)=\left(2.2^m+1\right)\left(2^m+1\right)=\)

\(=2.2^{2m}+3.2^m+1=2.4^m+3.2^m+1=A\)

+ Với \(m=1\Rightarrow A=2.4+3.2+1=15⋮3\)

+ Giả sử \(m=k\Rightarrow2.4^k+3.2^k+1⋮3\) ta cần chứng minh \(m=k+1\Rightarrow A⋮3\)

+ Với \(m=k+1\Rightarrow A=2.4^{k+1}+3.2^{k+1}+1=\)

\(=2.4^k.4+3.2^k.2+1=\left(2.4^k+3.2^k+1\right)+6.4^k+3.2^k=\)

\(=\left(2.4^k+3.2^k+1\right)+3\left(2.4^k+2^k\right)\)

Ta có \(2.4^k+3.2^k+1⋮3;3.\left(2.4^k+2^k\right)⋮3\Rightarrow A⋮3\)

Kết luận \(A⋮3\forall m\)

Question 4: There are 38 students in the class 5A. The students can be sit at 11 tables with no empty seats. There are small table for 3 students and large tables for 4 students. How many small tables and large tables in the class? 14

2cm=0,02m

2cm=0,02m

a. 10

HT

5⁴ . 20⁴/25⁵ . 45

TL: 

\(\frac{5^4.20^4}{25^5.4^5}=\frac{5^4.5^4.4^4}{(5^2)^5.4^5}=\frac{5^85^4}{5^{10}.4^5}=\frac{1}{25.4}=\frac{1}{100}\)

Sửa đề:

\(\frac{5^4.20^4}{25^5.4^5}\)

\(=\)\(\frac{5^4.5^4.4^4}{\left(5^2\right)^5.4^5}\)

\(=\)\(\frac{5^8.4^4}{5^{10}.4^5}\)

\(=\)\(\frac{1}{25.4}\)

\(=\)\(\frac{1}{100}\)

2^x+x = 20

2^x+x= 2⁴ + 4

\(\Rightarrow x=4\)

~HT~