1. Giải phương trình: \(\dfrac{x-3}{2011}\) + \(\dfrac{x-2}{2012}\) = \(\dfrac{x-2012}{2}\) +\(\dfrac{x-2011}{3}\)

2.Chứng tỏ phương trình sau vô nghiệm: x² + 1= x

1. We invited a pop star onto the chat show, but he didn't turn up

➞The pop star.............................................................................

2. She had to do the washing up but she didn't

➞She forgot...............................................................................

3.Don't leave the lights on all night, you will waste electricity

➞If..........................................................................................

4.Since the invention of computer, people have saved a lot of time

➞Since the computer was...............................................................

REWRITE THE FOLLOWING SETENCES THAT KEEP THE SAME MEANING

1.I was going to leave, but because of what he said, i didn't

➙She persuaded..................................................................

2. He never suspected that the money had been stolen

➞At no time...............................................................

3. He was very sorry that he didn't see Andrey on her trip to London

➞He greatly regretted...........................................................................

4.It's thought that the accident was caused by human error

➞The accident is................................................................

5. People thought that he cover was made of iron

➞The cover........................................................................

dap so la 30 em

Bài 1. Cho tứ giác ABCD. Gọi P, Q, R, S lần lượt là trung điểm của các cạnh AB, AC, CD và BD

1. Chứng minh tứ giác PQRS là hình bình hành

2. Tìm điều kiện của tứ giác ABCD để tứ giác PQRS là:

a) hình chữ nhật b) hình thoi c) hình vuông