Có 6n+3 chia hết cho 3n-1

=>2.(3n-1)+5 chia hết cho 3n-1

=>5 chia hết cho 3n-1

=>3n-1 thuộc Ư(5)={1;5;-1;-5}

=>n =2

Vậy....

Ko chắc lắm đâu sai thì xl bn

Ta có:

\(\frac{6n+3}{3n-1}=\frac{6n-2+5}{3n-1}=\frac{2\left(3n-1\right)+5}{3n-1}=2+\frac{5}{3n-1}\)

vì 6n+3 chia hết cho 3n-1 nên

3n-1 thuộc Ư(5)

Ư(5)={-1;1;-5;5}

Với 3n-1=-1

=>n=0

Với 3n-1=1 =>n=2/3

Với 3n-1=-5 =>n=-4/3

Với 3n-1=5 =>n=2

Vậy n={0;2/3;-4/3;2}

1) longest

2) tallest

3) more handsome

4) the noisest

1. longest

2.tallest

3.more handsome

4. the nosiest

\(\frac{x}{x+2}=\frac{3}{2}\left(x\ne-2\right)\)

<=> 2x=3x+6

<=> 2x-3x=6

<=> -x=6

<=> x=-6(tmđk)

Vây x=-6

\(\frac{x}{x+2}=\frac{3}{2}\)

\(\Rightarrow2x=3x+6\)

   \(-6=3x-2x\)

   \(-6=x\)

Vậy x=-6

\(\frac{x}{x+2}=\frac{3}{2}\)

\(\Rightarrow2x=3.\left(x+2\right)\)

\(\Rightarrow2x=3x+6\)

\(\Rightarrow3x+6=2x\)

\(\Rightarrow3x-2x=-6\)

\(\Rightarrow1x=-6\)

\(\Rightarrow x=-6\left(TM\right).\)

Vậy \(x=-6.\)

Chúc bạn học tốt!

\(\frac{x}{x+2}=\frac{3}{2}\)

\(2x=3x+6\)

\(2x-3x-6=0\)

\(-x=6\)

\(x=-6\)

Gọi (2n+1,2n+3) là d. ĐK  : \(d\inℕ^∗\)

Ta có : (2n+1,2n+3)=d

\(\Rightarrow\hept{\begin{cases}2n+1⋮d\\2n+3⋮d\end{cases}}\)

\(\Rightarrow\)(2n+3)-(2n+1)\(⋮\)d

\(\Rightarrow\)2\(⋮\)d

\(\Rightarrow d\inƯ\left(2\right)=\left\{\pm1;\pm2\right\}\)

Mà 2n+1 là số nguyên lẻ nên \(d=\pm1\)

\(\Rightarrow\left(2n+1,2n+3\right)=\pm1\)

\(\Rightarrow\)2n+1 và 2n+3 là 2 số nguyên tố cùng nhau

\(\Rightarrow\)Phân số \(A=\frac{2n+1}{2n+3}\)tối giản với mọi số tự nhiên n  (đpcm)

Cuộc khởi nghĩa Lam Sơn ở Thanh Hóa, Lê Lợi nhận gươm thần ở đây là đúng. Nhưng trả gươm lại ở Thăng Long vì đây là cố đô, là thủ đô của đất nước. Nó là biểu tượng cho sự nghiệp xây dựng hòa bình phồn vinh cua toàn dân tộc trong giai đoạn thái bình. Việc tả gươm ở Thăng Long là một ngụ ý của Long Vương: yêu cầu vua phải trị nước trong thời bình để “thuận thiên”. Hai không gian là hai thời kì, hai sứ mệnh của Lê Lợi.

Nguồn: Nguyễn Bảo Trung (h.vn)

cảm ơn <3

-18<x<17

\(\Rightarrow x\in\left\{-18;-17;-16;...;17\right\}\)

-27<x<27

\(\Rightarrow x\in\left\{-27;-26;-25;...;27\right\}\)

|x|<3

\(\Rightarrow x\in\left\{\pm1;\pm5\right\}\)

|-x|<5

\(\Rightarrow x\in\left\{\pm1\right\}\)

chúc bạn học tốt !!!

X \(\in\){ -19;-18;-17;-16;-15;-14;-13;-12;-11;-10;-9;-8;-7;-6;-5;-4;-3;-2;-1;0;1;2;3;4;5;6;7;8;9;10;11;12;13;14;15;16;17;18;19;20}

a) 2.3.5+7.8.9 chia hết cho 2

vì : 2 chia hết cho 2-> 2.3.5 ci hết cho 2 và 8 chi hết cho 2-> 7.8.9 chia hết cho 2

vì 2 số hạng chia hết cho 2=> tổng chi hết cho 2

b) tương tự: số  trừ chia hết cho 2 nhưng số bị trừ k chia hết cho 2

=> hiệu này k chia hết cho 2

HOK TOT~!!!

có chia hết cho 2 vì có viết ra số thập phân được

Summer vacations are the best time to relax and enjoy with family and friends, it’s the time I eagerly waited for every year. This year’s summer vacation is so special to me because it was the first time I’ve been on a trip with my colleagues. We had a wonderful time in Vung Tau – the city which has most beatiful beaches in Vietnam.

We stayed there for 2 days at a small but convenient hostel. First day, we got up early to see the sunrise on the beach. It’s the most gorgeous thing I’ve ever seen. Then we swam and lay down on the sand to enjoy beautiful sunlight and the clear blue sky. We also enjoyed delicious seafood and drank fresh coconuts.

The next day, it took us about 30 minutes to hike up the Small Mountain to visit the Lighthouse. But it was really worth the try! The lighthouse affords a panoramic magnificent view of the whole of Vung Tau and is a really interesting site. On top of Small Mountain, there is the enormous 28m figure of Jesus gazing across the East Sea. This is the largest sculpture in the Southern Vietnam. The two shoulders of the figure are balconies, each able to accommodate up to six people, which offer a splendid view of the surrounding landscape.

The weather during the time we stayed was really good and the local people were friendly. We took many photographs to save our memorable vacation and bought a lot of souvenirs, too. I just had so many good memories of that whole trip. Everything was great, but what made the trip even greater was the fact that I was able to bulid a stronger relationships with my colleagues.

#tham khảo

Summer vacations are the best time to relax and enjoy with family and friends, it’s the time I eagerly waited for every year. This year’s summer vacation is so special to me because it was the first time I’ve been on a trip with my colleagues. We had a wonderful time in Vung Tau – the city which has most beatiful beaches in Vietnam.

We stayed there for 2 days at a small but convenient hostel. First day, we got up early to see the sunrise on the beach. It’s the most gorgeous thing I’ve ever seen. Then we swam and lay down on the sand to enjoy beautiful sunlight and the clear blue sky. We also enjoyed delicious seafood and drank fresh coconuts.

The next day, it took us about 30 minutes to hike up the Small Mountain to visit the Lighthouse. But it was really worth the try! The lighthouse affords a panoramic magnificent view of the whole of Vung Tau and is a really interesting site. On top of Small Mountain, there is the enormous 28m figure of Jesus gazing across the East Sea. This is the largest sculpture in the Southern Vietnam. The two shoulders of the figure are balconies, each able to accommodate up to six people, which offer a splendid view of the surrounding landscape.The weather during the time we stayed was really good and the local people were friendly. We took many photographs to save our memorable vacation and bought a lot of souvenirs, too. I just had so many good memories of that whole trip. Everything was great, but what made the trip even greater was the fact that I was able to bulid a stronger relationships with my colleagues.