bài 3 : Thay x = -1 vào đa thức P , ta được:

3\(\times\)(-1)+5= -3 + 5= 2

Tiếp tục thay vào mà tính

b) Ta có :3\(\times\) \(x^2\)\(\ge\)0 với \(\forall\) x

=> 3\(x^2\)+5 \(\ge\)5 với \(\forall\) x

Vậy đa thức P luôn luôn dương với mọi giá trị của x

bài 2 :

Số tuổi của chị gái Minh : 13 + x

Số tuổi của bố Minh : 3(13+x)= 39+3x

Tổng số tuổi của ba bố con : 13+ 13 + x + 39+3x= 4x+65

I prefer going to the cinema to reading books at home

They are talking about a different type of footprint .

1. I/ please/ that/ you/ your family/ well.

I'm pleasant that you and your family are well

2. Here/ photo/ my family/ and/ let/ tell/ you/ us.

Here is a photo about my family and let me tell you about us

3. Father/ mechanic/ and/ work/ factory/ suburb.

My father is mechanic and he works at the factory near the suburb .

4. He/ work/ five/ days/ a week.

He works five days a week

5. He usually/ work/ morning/ so he/ free/ every morning.

He usually works in the morning so he isn't free every morning

6. In free time/ father/ often go/ play badminton.

In free time , my father often goes and plays badminton.

7. mother/ teacher/ and teach/ math/ school/ near/ house.

My mother is a teacher and teaches math at the school near my house .

8. So he/ have/ lot/ time/ take care/ house/ and /look/ me.

So she has a lot of times to take care of house and look after me .

9. Brother/ 17 years/ and /he/ grade 6.

My brother is 17 years old and he is in grade 6 ( gì cơ ?)

10. He/ love/ collect /stamps/ and have/ hundred/ stamps/ his collection.

He loves collecting stamps and have hundred stamps in his collection

11. please write/ me soon/ and tell/ more/ your/ family.

Please write to me soon and tell me more about your family .

ABCD ở đâu ? ( bn bôi đen đi )