Think of all the things you throw away: juice bottles, soft drink cans, candy wrappers. It adds up. (1) ……………. much trash do you produce?

Americans throw away an average of one ton of trash per person (2) …………… year. Most of this trash gets buried (3) ………… big holes in the ground called landfills. A lot of this garbage can be recycled, or turn back (4) ………… something useful. Just about any material can be recycle. The main things we recycle today are (5) ………… from metal, paper, glass, or plastic    People recycle for many reasons. One of the (6) …………. reasons is to conserve resources. Making new aluminum cans out old ones means less aluminum is needed (7) ………… new cans. This leads to a second reason people recycle: It saves energy. Recycling old aluminum cans takes a lot (8) ………… energy than making new aluminum. To make new aluminum, you (9) …………. to mine metal ore from the ground, remove the impurities, and refine it into a finished metal. Recycle also conserves valuable land. (10) ……… recycling, we produce less garbage. That means fewer landfills are needed for dumping our trash.

Cho sơ đồ phản ứng:
CH₄+O₂->CO₂+H₂O
Đốt cháy hoàn toàn 1,12 lít khí CH₄. Tính thể tích khí oxi cần dùng và thể tích khí CO₂ tạo thành ( thể tích các khí đo ở đktc )

Thực hiện các phép tính sau:

A = (x⁴-x²+ 2x -1) : (x²+ x -1) - (x²-x)

B = \(\dfrac{x+1}{x-2}+\dfrac{4}{x+2}+\dfrac{2-7x}{x^2-4}\)

Tách hạng tử để phân tích đa thức thành nhân tử:
a) x²+x-2
b) 2x²+5x+3
c) 3x²+5x-2