Làm thử nha .

\(a,\)Ta có :

\(789^{123}=789^{100}.789^{23}\)

\(1000^{10}=10^{3^{10}}=10^{30}\)

Vì \(789^{100}>10^{30}\)( thấy rõ )

=> 789¹⁰⁰.789²³ > 10³⁰

Hay \(789^{123}>1000^{10}\)

789¹²³>1000¹⁰

124⁸⁷⁵<999⁸⁸⁸

^{tt nnha}

\(\frac{4n+25}{n+2}=\frac{4n+8+17}{n+2}=\frac{4.\left(n+2\right)+17}{n+2}=4+\frac{17}{n+2}\)

\(4\in Z\Rightarrow n+2\inƯ\left(17\right)\)

\(\Rightarrow n+2\in\left\{-17;-1;1;17\right\}\)

\(\Rightarrow n\in\left\{-19;-3;-1;15\right\}\)

\(72^{45}-72^{44}=72^{44}.\left(72-1\right)=72^{44}.71\)

\(72^{44}-72^{43}=72^{43}.\left(72-1\right)=72^{43}.71\)

Vì \(72^{44}>72^{43}\Rightarrow72^{45}-72^{44}>72^{44}-72^{43}\)

a)\(\frac{27-5n}{n}=\frac{27}{n}-\frac{5n}{n}=\frac{27}{n}-5\)

\(\Rightarrow n\inƯ\left(27\right)=\left\{-27;-9;-3;-1;1;3;9\right\}\)

b)\(\frac{n+6}{n+2}=\frac{n+2+4}{n+2}=\frac{n+2}{n+2}+\frac{4}{n+2}=1+\frac{4}{n+2}\)

\(\Rightarrow n+2\inƯ\left(4\right)=\left\{-4;-2;-1;1;2;4\right\}\)

\(\Rightarrow n\in\left\{-6;-4;-3;-1;0;2\right\}\)

(n+6) chia hết cho (n+2)

=> (n+4+2) chia hết cho (n+2)

=> 4.(n+2) ( do n+2 chia hết cho n+2)

=> n+2 thuộc {1;4}

=> n thuộc {2}

Vậy n thuộc {2}

25 mũ 30 lớn hơn

125 mũ 19 lớn hơn 

Chắc chắn 100%

2^2.8^27>16^25 mk nha

2^2*8^27>16^25 ok

Thank

a) 6x2y (có gạch ngang trên đầu) chia hết cho 9 => 6 + x + 2 + y chia hết cho 9 => 8 + x + y chia hết cho 9

=> x + y = {1;10}

- Trường hợp 1: x + y = 1.

Nếu x + y = 1 thì x = (1 + 1) : 2 = 1.

=> y = 0.

- Trường hợp 2: x + y = 10

Nếu x + y = 10 thì x = (10 + 1) : 2 = 5,5 (loại)

Vậy x = 1, y = 0.

b) \(\frac{2x+12}{x+1}=\frac{2x+2+10}{x+1}=\frac{2.\left(x+1\right)}{x+1}+\frac{10}{x+1}=2+\frac{10}{x+1}\)

Mà \(2\in Z\Rightarrow x+1\inƯ\left(10\right)\)

\(\Rightarrow x+1\in\left\{-10;-5;-2;-1;1;2;5;10\right\}\)

\(\Rightarrow x\in\left\{-11;-6;-3;-2;0;1;4;9\right\}\)

nhanh len ai lam dung toi tck cho toi con phai di hoc