bài 1)

a)\(\dfrac{-1}{39}+\dfrac{-1}{52}\)

\(=\dfrac{-4}{156}+\dfrac{-3}{156}\)

\(=\dfrac{-7}{156}\)

b)\(\dfrac{-6}{9}+\dfrac{-12}{16}\)

\(=\dfrac{-96}{144}+\dfrac{-108}{144}\)

\(=\dfrac{-204}{144}\)

\(=\dfrac{-17}{12}\)

dạ em cảm ơn ah :>

câu 18) B

lúc trả lời có hình chữ M ở góc trên bên trái đó bạn

câu 1 sai mẫu số nha

Bài 2)

+ Hai mươi sáu phần mười: \(\dfrac{26}{10}\)

+ Chín phần trăm: \(\dfrac{9}{100}\)

+ Ba mươi tư phần nghìn: \(\dfrac{34}{1000}\)

+ Hai trăm bảy mươi lăm phần triệu: \(\dfrac{275}{1000000}\)

:)
 

VI)

1.am

2.in

3.in

4.in

5.are

6.in

7.with

8.than

9.of

10.many

11.than

12.more

bài 1)
a) \(\dfrac{\left(-3\right)^{10}.15^5}{25^3.\left(-9\right)^7}\)

\(=\dfrac{\left(-3\right)^{10}.\left(3.5\right)^5}{\left(5^2\right)^3.\left(-3.3\right)^7}\)

\(=\dfrac{\left(-3\right)^{10}.3^5.5^5}{5^6.\left(-3\right)^7.3^7}\)

\(=\dfrac{\left(-3\right)^3.1.1}{5.1.3^2}\)

\(=\dfrac{-27.1.1}{5.1.9}\)

\(=\dfrac{-27}{45}\)

\(=\dfrac{-9}{15}\)

b)\(2^3+3.\left(\dfrac{1}{9}\right)^0-2^{-2}.4\left[\left(-2\right)^2:\dfrac{1}{2}\right].8\)

\(=8+3.1-\dfrac{1}{2^2}.4+\left[\left(4:\dfrac{1}{2}\right)\right].8\)

\(=8+3.1-\dfrac{1}{4}.4+\left[4.\dfrac{2}{1}\right].8\)

\(=8+3.1-\dfrac{1}{4}.4+8.8\)

\(=8+3-1+64\)

\(=11-1+64\)

\(=10+64\)

\(=74\)

\(\dfrac{1}{2}-\left(\dfrac{1}{3}+\dfrac{3}{4}\right)\le x\le\dfrac{1}{24}-\left(\dfrac{1}{8}-\dfrac{1}{3}\right)\)

\(\dfrac{1}{2}-\left(\dfrac{4}{12}+\dfrac{9}{12}\right)\le x\le\dfrac{1}{24}-\left(\dfrac{3}{24}-\dfrac{8}{24}\right)\)

\(\dfrac{1}{2}-\dfrac{13}{12}\le x\le\dfrac{1}{24}-\dfrac{-5}{24}\)

\(\dfrac{6}{12}-\dfrac{13}{12}\le x\le\dfrac{1}{24}+\dfrac{5}{24}\)

\(\dfrac{-7}{12}\le x\le\dfrac{6}{24}\)

\(\dfrac{-14}{24}\le x\le\dfrac{6}{24}\)

\(\Rightarrow x=\left\{\dfrac{-14}{24};\dfrac{-13}{24};\dfrac{-12}{24};...;\dfrac{6}{24}\right\}\)