Hãy xác định những thông tin sau là Đúng (True) hay Sai (False).

The school year in Vietnam runs from September through the first of June. It is divided into two semesters. The first semester begins in September and ends before the Lunar New Year, while the second one begins right after the first one and lasts until June the first. Children in Vietnam go to school six days a week from Monday to Saturday and a typical school day runs from 7:00 to about 11:30 in the morning. Vietnamese students are expected to take school very seriously and to work hard. Most periods begin with a small test. The teacher calls on some students to stand and answer a few questions to check their understanding of the last lesson.

After school, Vietnamese students take part in a lot of activities. Some students play sports. Soccer, table tennis, and badminton are the most popular. Others enjoy going swimming. A few students like music and movies. They often practice playing musical instruments in the music hall or go to the cinema with their friends to see the latest films. In addition, some students play video games or computer games or stay at home to help their parents. The after-school activities above help students find friends with similar interests, develop their talents, and sometimes even discover their career goals.

No one expects students to take school seriously and to work hard in Vietnam.

A. True

B. False

Vật kính của một kính thiên văn có tiêu cự 90 cm, thị kính có tiêu cự 2,5 cm. Người quan sát có điểm cực cận cách mắt 20 cm, điểm cực viễn ở vô cực, đặt mắt sát thị kính để quan sát một chòm sao.Tính khoảng cách giữa vật kính và thị kính khi ngắm chừng ở cực cận.

chữ bt mà có nhỏ quá đâu

vẫn dọc dc mà

ta có:

g) \(\sqrt{2x^2+1}+\dfrac{2}{3-2x}\)

đkxd của pt là \(\left\{{}\begin{matrix}2x^2+1\ge0\\3x-2\ne0\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}2x^2+1\ge0\left(luondung\right)\\3x\ne2\end{matrix}\right.\Leftrightarrow x\ne\dfrac{3}{2}\)

vậy kết luận là xong

ok

ta có :

\(\dfrac{1+x}{3-x}-\dfrac{1-2x}{3+x}-\dfrac{x\cdot\left(1-x\right)}{9-x^2}\)

= \(\dfrac{\left(1+x\right)\cdot\left(3+x\right)}{\left(3-x\right)\cdot\left(3+x\right)}-\dfrac{\left(1-2x\right)\cdot\left(3-x\right)}{\left(3+x\right)\cdot\left(3-x\right)}-\dfrac{x\cdot\left(1-x\right)}{\left(3-x\right)\cdot\left(3+x\right)}\)

= \(\dfrac{3+x+3x+x^2-3+x+6x-2x^2-x+x^2}{\left(3+x\right)\cdot\left(3-x\right)}\)

= \(\dfrac{10x}{9-x^2}\)

bài lm có j sai sót mong bn thông cảm .

69 + x = 98

=> x = 98 - 69

=> x = 29

nghĩa là ko bao h bỏ cuộc

ok

Hiệu là : 

    10,5 + 10,5=21

nếu cùng thêm cả 2 số thì hiệu ko thay đổi

SL là:

     21 : (4-1) x 4 = 28

SB là : 

    21 : (4-1) x 1 = 7