Cho đường tròn tâm K bàng tiếp trong góc A , tiếp xúc với AB , AC , BC tại M, N , E . Chứng minh :

a) AM = AN = P

b) BM = BE = p - c

( P là nửa chu vi tam giác ABC , c là cạnh AB )

Giải phương trình :

( Chú ý : nêu công thức của phương pháp )

\(\sqrt{1+x}+\sqrt{8-x}-\sqrt{\left(1+x\right)\left(8-x\right)}=3\)

Cho a và b là hai sô' tự nhiên thoả mãn (a + 3) và (b + 4) cùng chia hết cho 5. Chứng minh a 2   +   b 2  cũng chia hết cho 5.

Cho a, b là các số nguyên. Chứng minh rằng 6a + 11b chia hết cho 31 khi và chỉ khi a + 7b chia hết cho 31

Tìm cặp số nguyên x, y sao cho  x y   -   2 x   -   2 y   =   0

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks from 31 to 35.

In Germany, it's important to be serious in a work situation. They don't mix work and play so you shouldn't make jokes (31) ______ you do in the UK and USA when you first meet people. They work in a very organized way and prefer to do one thing at a time. They don't like interruptions or (32) ______changes of schedule. Punctuality is very important so you should arrive on time for appointments. At meeting, it’s important to follow the agenda and not interrupt (33) ______speaker. If you give a presentation, you should focus (34) ______ facts and technical information and the quality of your company's products. You should also prepare well, as they may ask a lot of questions. Colleagues normally use the family names, and title - for example 'Doctor' or 'Professor', so you shouldn't use first names (35) ______ a person asks you to.

Điền vào ô 31.

A. while

B. as if

C. such as

D. as

Mark the letter A, B, C or D on your answer sheet to indicate the word(s) OPPOSITE in meaning to the underlined word(s) in each of the following questions.

Although it’s a long day for us, we feel we are contented with what we do.

A. interested

B. dissatisfied

C. excited

D. shocked