Put in the correct prepositions in the blank.

It is now almost certain that global warming has been directly caused (1)................man's use of fossil fuels.This has led (2)........an international debate about what we should do to reducethe negative effects (3)........our actions and how we can make the planet safe for our children to live in. One consequence (4)...........this debate has been to improve the level of "green" education in schools and this should result (5)......... greater awareness of thí difficult issue in the long term. However, in the short term there still remains much to be done. The reason (6)....this is that we need to address causes (7).....................the immediate problem.

cho biểu thức: A= [\(\frac{3}{2}.\left(x^4-\frac{x^4+1}{x^2+1}\right).\frac{x^3-x\left(4x-1\right)-4}{x^7+6x^6-x-6}\)]: \(\frac{x^2+29x+78}{3x^2+12x-36}\)

a. Rút gọn A

b.Tìm x nguyên để A có giá trị nguyên

Chứng tỏ rằng đa thức :

A = (x² + 1)⁴ + 9(x²+1)³ + 21(x² + 1)² - x² = 31 luôn không âm với mọi giá trị của biến

1.Tính nhanh:

a. 202² - 54² + 256.352 b. 621 - 769.373 - 148²

c. \(\frac{42^2-10^2}{\left(36,5\right)^2-\left(27,5\right)^2}\) d. S = \(\frac{93^2+83^2}{180}\) - 97.83

2.Tìm 4 số nguyên liên tiếp biết tích của chúng bằng 120