Với x ≥ 0 ⇒ x + 1, x + 2, x + 3, x + 4 đều > 0

⇒ P = (x + 1). (x + 2). (x + 3). (x + 4) + 1 > 0
Với -1 ≤ x ≤ -4 thì P = (x + 1). (x + 2). (x + 3). (x + 4) + 1 > 0

Với x < -4 ⇒ x + 1, x + 2, x + 3, x + 4 đều < 0

⇒ P = (x + 1). (x + 2). (x + 3). (x + 4) + 1 > 0

Vậy ∀ x thì

The doctor advises her not to eat so many sweet.

a) \(\left|\dfrac{2}{7}\right|\) = \(\dfrac{2}{7}\)

b) \(\left|\dfrac{-5}{6}\right|\) = \(\dfrac{5}{6}\)

c) \(\left|4\dfrac{2}{3}\right|\) = \(4\dfrac{2}{3}\)

d) \(\left|-3,41\right|\) = \(3,41\)

Unless you study harder now, you wil have trouble taking the exam

A story is going to be told by the teacher

1. What is Mr Davy's nationality?

2. How many people there are in Mexico City?

3. What is the weather like now in London?

4. What is the height of Sears Tower?

5. Where does the Nile River flow to?

trắng = white

Có: A = 2020.2021 - 2022.2021² + 2021³

          = 2020.2021 - 2021².(2022 - 2021)

          = 2020.2021 - 2021²

          = 2021.(2020 - 2021)

          = 2021.(-1)

          = -2021

How many boards are there on the wall

TH₁: a là số tự nhiên ⇒ a ≥ 0 ⇒ a + 1 > 0

⇒ a. (a + 1) > 0 ⇒ a. (a + 1) + 1 > 0

TH₂: a là số nguyên âm và a ≤ -2 ⇒ a + 1 < 0

⇒ a. (a + 1) > 0 ⇒ a. (a + 1) + 1 > 0

TH₃: a = -1 ⇒a. (a + 1) + 1 = -1.0 + 1 = 1 > 0