2 bạn có số viên bi là:

            19+25=44 viên

                      đáp số:44 viên bi

Vì x(x - 5) < 0

⇒x và x - 5 là 2 số trái dấu nhau

Th1:

x < 0

⇒x - 5 > 0

⇒x - 5 > 5

Vô lí, và ko có số nào < 0 và > 5

⇒ LOẠI

Th2:

x > 0

⇒x - 5 < 0

⇒x - 5 < 5

⇒x ∈ {1; 2; 3; 4}

Vậy x ∈ {1; 2; 3; 4}

Complete the sentences by putting the verbs into the past continuous or past simple

1. .....Did.....they(thank).....thank.....you give them the money?

2. This time last time we (have).....had.....a wonderful time on beaches in Hawaii while some of our friends (work).......were working.....so hard.

3. When Nam(get).....got.....home,his father (do).....was doing.....the gardening while his mother (perpare).....was perparing.....dinner.

4. When i (arrive).....arrived.....at his flat,he(still,sleep).....still sleeping.....

5. She (water).....was watering.....the flowers in the garden while her next door neighbour (chat).....was chatting.....with her over the fence.

6. As we (cross).....were crossing.....the street,we (see).....saw.....an accident.

7. Who (be).....was.....the man you (talk).....were talking.....to? I (see).....saw.....him at the gate when i (come).....was coming.....in

8. We(wait).....were waiting.....for the bus when he (pass).....passed.....by and (offer).....offered.....us a lift.

9. When the students (hear).....heard.....the bell,the(get).....got.....up and (leave).....left.....

10. The bell(ring).....rang.....while Tom (have).....was having.....a bath

11. The children(play).....were playing.....football when their mother (come).....came.....back home

Số mới là: 105

Số cũ là: 15

ĐS:60 viên