Question

Bài 1: Tìm x:

a. \(\dfrac{3}{5}\) - 2(\(\dfrac{x}{2}\) + \(\dfrac{-5}{4}\)) = \(\dfrac{4}{6}\)

b. (\(\dfrac{x}{3}\)- \(\dfrac{1}{2}\))(2x+4) = 0

c. |\(\dfrac{x}{5}\)- 1| = \(\dfrac{1}{4}\)

d.|2x-\(\dfrac{4}{5}\)| = \(\dfrac{3}{4}\)

Bài 2: Tính:

a. \(\dfrac{3}{4\cdot6}\)+\(\dfrac{3}{6\cdot8}\)+...............+\(\dfrac{3}{82\cdot84}\)

b. \(\dfrac{5}{3\cdot7}\)+\(\dfrac{5}{7\cdot11}\)+\(\dfrac{5}{11\cdot15}\)+\(\dfrac{5}{15\cdot19}\)

Bài 3: Cho Q = \(\dfrac{3}{10}\)+\(\dfrac{3}{11}\)+\(\dfrac{3}{12}\)+\(\dfrac{3}{13}\)+\(\dfrac{3}{14}\). Chứng minh rằng 1<Q<2. Từ đó suy ra Q không phải là số tự nhiên.

Answer 1

https://i.imgur.com/7ARysDs.jpg

Answer 2

Tặng kèm nèèèèèèè!!!!!!!!!!!!