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2 tháng 11 2021

Câu nào bạn ơi

 

2 tháng 11 2021

Câu 19,20

16 tháng 5 2022

12 What do you often do after school?

13 What is he doing now?

14 Where are you often have dinner?

15 What is Lan going to buy

16 Where are they going to stay?

17 Why do you like learning English?

18 How many pens does she want>

19 What does Nam have for for lunch

20 How many books does Ha have in the bags?

16 tháng 5 2022

12. What do you often do after school?

13. What is he doing now?

14. Where do you often have dinner? 

15. What is Lan going to buy?
16. Where are they going to stay?

 17. Why do you like learning English?
18. How many pens does she want?

19. What does Nam have for lunch? 

20. How many books does Ha have in the bags? 

26 tháng 11 2021

9. Has the work been done by him?

10. The boxes were opened and cigarettes were taken out by us

11. She was given a new one

12. He is proved wrong

13. We were promised higher wages

14. This is the third time we have been written to about this by them

15. We were asked to be there at 8 o'clock

16. She is being shown how to do it

18-3x6x7=18-18x7=18x(1-7)=18x(-6)=-108

28 tháng 2 2020

18-3.6.7

=18-18.7

=18.(1-7)

=18.-6

=-108

8 tháng 5 2022

hình thì đăng 1 câu thôi:)

8 tháng 5 2022

Giúp ik

a) Ta có: \(x^2-3=0\)

nên \(x^2=3\)

hay \(x\in\left\{\sqrt{3};-\sqrt{3}\right\}\)

b) Ta có: \(4x^2-9=0\)

\(\Leftrightarrow\left(2x-3\right)\left(2x+3\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{3}{2}\\x=-\dfrac{3}{2}\end{matrix}\right.\)

c) Ta có: \(\left(x+2\right)^2-\left(x-2\right)^2=5\)

\(\Leftrightarrow x^2+4x+4-x^2+4x-4=5\)

\(\Leftrightarrow8x=5\)

hay \(x=\dfrac{5}{8}\)

d) Ta có: \(\left(x+2\right)^3-x^3+6x^2=7\)

\(\Leftrightarrow x^3+6x^2+12x+8-x^3+6x^2-7=0\)

\(\Leftrightarrow12x^2+12x+1=0\)

\(\Delta=12^2-4\cdot12\cdot1=144-48=96\)

Vì Δ>0 nên phương trình có hai nghiệm phân biệt là:

\(\left\{{}\begin{matrix}x_1=\dfrac{-12-4\sqrt{6}}{24}=\dfrac{-3-\sqrt{6}}{6}\\x_2=\dfrac{-12+4\sqrt{6}}{24}=\dfrac{-3+\sqrt{6}}{6}\end{matrix}\right.\)

e) Ta có: \(\left(x-2\right)^2-\left(x-1\right)\left(x+1\right)=7\)

\(\Leftrightarrow x^2-4x+4-x^2+1=7\)

\(\Leftrightarrow-4x=2\)

hay \(x=-\dfrac{1}{2}\)

a) Ta có: \(P\left(x\right)=7x^3+3x^4-x^2+5x^2-6x^3-2x^4+2017-x^3\)

\(=x^4+4x^2+2017\)

b) Bậc của P(x) là 4

c) Các hệ số của P(x) là 1;4;2017

Hệ số cao nhất là 4

Hệ số tự do là 2017

d) \(P\left(0\right)=0^4+4\cdot0^2+2017=2017\)

\(P\left(1\right)=1^4+4\cdot1^2+2017=1+4+2017=2022\)

\(P\left(-1\right)=\left(-1\right)^4+4\cdot\left(-1\right)^2+2017=1+4+2017=2022\)

e) \(P\left(-a\right)=\left(-a\right)^4+4\cdot\left(-a\right)^2+2017=a^4+4a^2+2017\)

\(P\left(a\right)=a^4+4a^2+2017\)

Do đó: P(-a)=P(a)